From 0e2afb6a3ae5ba0c94880dc3efdaa3a0b4b6870c Mon Sep 17 00:00:00 2001
From: Billy Chan <ccw.billy.123@gmail.com>
Date: Wed, 7 Jun 2023 16:41:05 +0800
Subject: [PATCH 01/17] Parse MySQL column default value

---
 src/mysql/def/column.rs      | 10 +++++++---
 src/mysql/parser/column.rs   | 15 ++++++++++++++-
 src/mysql/writer/column.rs   | 19 +++++++++++++------
 tests/live/mysql/src/main.rs | 21 ++++++++++++++++++++-
 4 files changed, 54 insertions(+), 11 deletions(-)

diff --git a/src/mysql/def/column.rs b/src/mysql/def/column.rs
index 7ce262a6..61d7ce48 100644
--- a/src/mysql/def/column.rs
+++ b/src/mysql/def/column.rs
@@ -41,9 +41,13 @@ pub enum ColumnKey {
 
 #[derive(Clone, Debug, PartialEq)]
 #[cfg_attr(feature = "with-serde", derive(Serialize, Deserialize))]
-pub struct ColumnDefault {
-    /// default value expression
-    pub expr: String,
+pub enum ColumnDefault {
+    Int(i32),
+    Double(f64),
+    String(String),
+    CurrentDate,
+    CurrentTime,
+    CurrentTimestamp,
 }
 
 #[derive(Clone, Debug, PartialEq)]
diff --git a/src/mysql/parser/column.rs b/src/mysql/parser/column.rs
index 2a9f266a..e4cac8b6 100644
--- a/src/mysql/parser/column.rs
+++ b/src/mysql/parser/column.rs
@@ -264,7 +264,20 @@ pub fn parse_column_default(column_default: Option<String>) -> Option<ColumnDefa
     match column_default {
         Some(default) => {
             if !default.is_empty() {
-                Some(ColumnDefault { expr: default })
+                let column_default = if let Some(int) = default.parse::<i32>().ok() {
+                    ColumnDefault::Int(int)
+                } else if let Some(double) = default.parse::<f64>().ok() {
+                    ColumnDefault::Double(double)
+                } else if default == "CURRENT_DATE" {
+                    ColumnDefault::CurrentDate
+                } else if default == "CURRENT_TIME" {
+                    ColumnDefault::CurrentTime
+                } else if default == "CURRENT_TIMESTAMP" {
+                    ColumnDefault::CurrentTimestamp
+                } else {
+                    ColumnDefault::String(default)
+                };
+                Some(column_default)
             } else {
                 None
             }
diff --git a/src/mysql/writer/column.rs b/src/mysql/writer/column.rs
index bd55b0e3..49421924 100644
--- a/src/mysql/writer/column.rs
+++ b/src/mysql/writer/column.rs
@@ -1,6 +1,7 @@
-use crate::mysql::def::{CharSet, ColumnInfo, NumericAttr, StringAttr, Type};
+use crate::mysql::def::{CharSet, ColumnDefault, ColumnInfo, NumericAttr, StringAttr, Type};
 use sea_query::{
-    Alias, BlobSize, ColumnDef, DynIden, EscapeBuilder, Iden, IntoIden, MysqlQueryBuilder,
+    Alias, BlobSize, ColumnDef, DynIden, EscapeBuilder, Iden, IntoIden, Keyword, MysqlQueryBuilder,
+    SimpleExpr,
 };
 use std::fmt::Write;
 
@@ -15,10 +16,16 @@ impl ColumnInfo {
             col_def.auto_increment();
         }
         let mut extras = Vec::new();
-        if let Some(default) = self.default.as_ref() {
-            let mut string = "".to_owned();
-            write!(&mut string, "DEFAULT {}", default.expr).unwrap();
-            extras.push(string);
+        if let Some(default) = &self.default {
+            let default_expr: SimpleExpr = match default {
+                ColumnDefault::Int(int) => (*int).into(),
+                ColumnDefault::Double(double) => (*double).into(),
+                ColumnDefault::String(string) => string.into(),
+                ColumnDefault::CurrentDate => Keyword::CurrentDate.into(),
+                ColumnDefault::CurrentTime => Keyword::CurrentTime.into(),
+                ColumnDefault::CurrentTimestamp => Keyword::CurrentTimestamp.into(),
+            };
+            col_def.default(default_expr);
         }
         if self.extra.on_update_current_timestamp {
             extras.push("ON UPDATE CURRENT_TIMESTAMP".to_owned());
diff --git a/tests/live/mysql/src/main.rs b/tests/live/mysql/src/main.rs
index afcf1d4a..dbb4a6d8 100644
--- a/tests/live/mysql/src/main.rs
+++ b/tests/live/mysql/src/main.rs
@@ -203,7 +203,26 @@ fn create_order_table() -> TableCreateStatement {
         .col(
             ColumnDef::new(Alias::new("placed_at"))
                 .date_time()
-                .not_null(),
+                .not_null()
+                .default(Expr::current_timestamp()),
+        )
+        .col(
+            ColumnDef::new(Alias::new("updated"))
+                .date_time()
+                .not_null()
+                .default("2023-06-07 16:24:00"),
+        )
+        .col(
+            ColumnDef::new(Alias::new("net_weight"))
+                .double()
+                .not_null()
+                .default(10.05),
+        )
+        .col(
+            ColumnDef::new(Alias::new("priority"))
+                .integer()
+                .not_null()
+                .default(5),
         )
         .index(
             Index::create()

From 43ed1840d8dbf1b254967ab767418f37f370c5f2 Mon Sep 17 00:00:00 2001
From: Billy Chan <ccw.billy.123@gmail.com>
Date: Wed, 7 Jun 2023 17:02:37 +0800
Subject: [PATCH 02/17] Fixup

---
 src/mysql/writer/table.rs    | 8 ++------
 tests/live/mysql/src/main.rs | 2 +-
 2 files changed, 3 insertions(+), 7 deletions(-)

diff --git a/src/mysql/writer/table.rs b/src/mysql/writer/table.rs
index 8c3f68b7..b78b0de0 100644
--- a/src/mysql/writer/table.rs
+++ b/src/mysql/writer/table.rs
@@ -119,9 +119,7 @@ mod tests {
                         null: false,
                         key: ColumnKey::NotKey,
                         default: Some(
-                            ColumnDefault {
-                                expr: "CURRENT_TIMESTAMP".to_owned(),
-                            },
+                            ColumnDefault::CurrentTimestamp,
                         ),
                         extra: ColumnExtra {
                             auto_increment: false,
@@ -219,9 +217,7 @@ mod tests {
                         null: false,
                         key: ColumnKey::NotKey,
                         default: Some(
-                            ColumnDefault {
-                                expr: "CURRENT_TIMESTAMP".to_owned(),
-                            },
+                            ColumnDefault::CurrentTimestamp,
                         ),
                         extra: ColumnExtra {
                             auto_increment: false,
diff --git a/tests/live/mysql/src/main.rs b/tests/live/mysql/src/main.rs
index dbb4a6d8..718070bd 100644
--- a/tests/live/mysql/src/main.rs
+++ b/tests/live/mysql/src/main.rs
@@ -2,7 +2,7 @@ use pretty_assertions::assert_eq;
 use regex::Regex;
 use sea_schema::mysql::{def::TableDef, discovery::SchemaDiscovery};
 use sea_schema::sea_query::{
-    Alias, ColumnDef, ForeignKey, ForeignKeyAction, Index, MysqlQueryBuilder, Table,
+    Alias, ColumnDef, Expr, ForeignKey, ForeignKeyAction, Index, MysqlQueryBuilder, Table,
     TableCreateStatement, TableRef,
 };
 use sqlx::{MySql, MySqlPool, Pool};

From be97301805077b37d968efd4d531cad3965d60cf Mon Sep 17 00:00:00 2001
From: Billy Chan <ccw.billy.123@gmail.com>
Date: Wed, 7 Jun 2023 17:02:40 +0800
Subject: [PATCH 03/17] clippy

---
 src/mysql/parser/column.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/mysql/parser/column.rs b/src/mysql/parser/column.rs
index e4cac8b6..b187fccb 100644
--- a/src/mysql/parser/column.rs
+++ b/src/mysql/parser/column.rs
@@ -264,9 +264,9 @@ pub fn parse_column_default(column_default: Option<String>) -> Option<ColumnDefa
     match column_default {
         Some(default) => {
             if !default.is_empty() {
-                let column_default = if let Some(int) = default.parse::<i32>().ok() {
+                let column_default = if let Ok(int) = default.parse::<i32>() {
                     ColumnDefault::Int(int)
-                } else if let Some(double) = default.parse::<f64>().ok() {
+                } else if let Ok(double) = default.parse::<f64>() {
                     ColumnDefault::Double(double)
                 } else if default == "CURRENT_DATE" {
                     ColumnDefault::CurrentDate

From 8c73afa18681cd364ef01aea011d9866500a8062 Mon Sep 17 00:00:00 2001
From: Billy Chan <ccw.billy.123@gmail.com>
Date: Wed, 7 Jun 2023 18:21:27 +0800
Subject: [PATCH 04/17] Fix

---
 src/mysql/parser/column.rs | 27 +++++++++++++++------------
 1 file changed, 15 insertions(+), 12 deletions(-)

diff --git a/src/mysql/parser/column.rs b/src/mysql/parser/column.rs
index b187fccb..018a1d19 100644
--- a/src/mysql/parser/column.rs
+++ b/src/mysql/parser/column.rs
@@ -264,20 +264,23 @@ pub fn parse_column_default(column_default: Option<String>) -> Option<ColumnDefa
     match column_default {
         Some(default) => {
             if !default.is_empty() {
-                let column_default = if let Ok(int) = default.parse::<i32>() {
-                    ColumnDefault::Int(int)
+                if let Ok(int) = default.parse::<i32>() {
+                    Some(ColumnDefault::Int(int))
                 } else if let Ok(double) = default.parse::<f64>() {
-                    ColumnDefault::Double(double)
-                } else if default == "CURRENT_DATE" {
-                    ColumnDefault::CurrentDate
-                } else if default == "CURRENT_TIME" {
-                    ColumnDefault::CurrentTime
-                } else if default == "CURRENT_TIMESTAMP" {
-                    ColumnDefault::CurrentTimestamp
+                    Some(ColumnDefault::Double(double))
+                } else if default == "CURRENT_DATE" || default == "current_date()" {
+                    Some(ColumnDefault::CurrentDate)
+                } else if default == "CURRENT_TIME" || default == "current_time()" {
+                    Some(ColumnDefault::CurrentTime)
+                } else if default == "CURRENT_TIMESTAMP" || default == "current_timestamp()" {
+                    Some(ColumnDefault::CurrentTimestamp)
+                } else if default.starts_with("'") && default.ends_with("'") {
+                    Some(ColumnDefault::String(default[1..(default.len()-1)].into()))
+                } else if default == "NULL" {
+                    None
                 } else {
-                    ColumnDefault::String(default)
-                };
-                Some(column_default)
+                    Some(ColumnDefault::String(default))
+                }
             } else {
                 None
             }

From 190c8a3bdbd1a00a4dd0c491395808c95cf2ab43 Mon Sep 17 00:00:00 2001
From: Billy Chan <ccw.billy.123@gmail.com>
Date: Wed, 7 Jun 2023 18:39:08 +0800
Subject: [PATCH 05/17] clippy

---
 src/mysql/parser/column.rs | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/mysql/parser/column.rs b/src/mysql/parser/column.rs
index 018a1d19..bae95609 100644
--- a/src/mysql/parser/column.rs
+++ b/src/mysql/parser/column.rs
@@ -274,8 +274,10 @@ pub fn parse_column_default(column_default: Option<String>) -> Option<ColumnDefa
                     Some(ColumnDefault::CurrentTime)
                 } else if default == "CURRENT_TIMESTAMP" || default == "current_timestamp()" {
                     Some(ColumnDefault::CurrentTimestamp)
-                } else if default.starts_with("'") && default.ends_with("'") {
-                    Some(ColumnDefault::String(default[1..(default.len()-1)].into()))
+                } else if default.starts_with('\'') && default.ends_with('\'') {
+                    Some(ColumnDefault::String(
+                        default[1..(default.len() - 1)].into(),
+                    ))
                 } else if default == "NULL" {
                     None
                 } else {

From 86f794bc4e019b06abaa17e28e9273d46dfe3621 Mon Sep 17 00:00:00 2001
From: Billy Chan <ccw.billy.123@gmail.com>
Date: Thu, 8 Jun 2023 19:44:53 +0800
Subject: [PATCH 06/17] Add ColumnDefault::Null

---
 src/mysql/def/column.rs    | 1 +
 src/mysql/parser/column.rs | 2 +-
 src/mysql/writer/column.rs | 1 +
 3 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/mysql/def/column.rs b/src/mysql/def/column.rs
index 61d7ce48..f0bbaaa0 100644
--- a/src/mysql/def/column.rs
+++ b/src/mysql/def/column.rs
@@ -45,6 +45,7 @@ pub enum ColumnDefault {
     Int(i32),
     Double(f64),
     String(String),
+    Null,
     CurrentDate,
     CurrentTime,
     CurrentTimestamp,
diff --git a/src/mysql/parser/column.rs b/src/mysql/parser/column.rs
index bae95609..079a40d7 100644
--- a/src/mysql/parser/column.rs
+++ b/src/mysql/parser/column.rs
@@ -279,7 +279,7 @@ pub fn parse_column_default(column_default: Option<String>) -> Option<ColumnDefa
                         default[1..(default.len() - 1)].into(),
                     ))
                 } else if default == "NULL" {
-                    None
+                    ColumnDefault::Null
                 } else {
                     Some(ColumnDefault::String(default))
                 }
diff --git a/src/mysql/writer/column.rs b/src/mysql/writer/column.rs
index 49421924..b3d18402 100644
--- a/src/mysql/writer/column.rs
+++ b/src/mysql/writer/column.rs
@@ -21,6 +21,7 @@ impl ColumnInfo {
                 ColumnDefault::Int(int) => (*int).into(),
                 ColumnDefault::Double(double) => (*double).into(),
                 ColumnDefault::String(string) => string.into(),
+                ColumnDefault::Null => Option::<bool>::None.into(),
                 ColumnDefault::CurrentDate => Keyword::CurrentDate.into(),
                 ColumnDefault::CurrentTime => Keyword::CurrentTime.into(),
                 ColumnDefault::CurrentTimestamp => Keyword::CurrentTimestamp.into(),

From 3f23b2e075e13748feaae497e0a3a9b36ae37b94 Mon Sep 17 00:00:00 2001
From: Billy Chan <ccw.billy.123@gmail.com>
Date: Thu, 8 Jun 2023 19:46:12 +0800
Subject: [PATCH 07/17] Parse extra to determine if it's default expression

---
 src/mysql/parser/column.rs | 38 ++++++++++++++++++++++----------------
 1 file changed, 22 insertions(+), 16 deletions(-)

diff --git a/src/mysql/parser/column.rs b/src/mysql/parser/column.rs
index 079a40d7..16073e62 100644
--- a/src/mysql/parser/column.rs
+++ b/src/mysql/parser/column.rs
@@ -15,7 +15,7 @@ pub fn parse_column_query_result(result: ColumnQueryResult) -> ColumnInfo {
         col_type: parse_column_type(&mut Parser::new(&result.column_type)),
         null: parse_column_null(&result.is_nullable),
         key: parse_column_key(&result.column_key),
-        default: parse_column_default(result.column_default),
+        default: parse_column_default(result.column_default, &result.extra),
         extra: parse_column_extra(&mut Parser::new(&result.extra)),
         expression: match result.generation_expression {
             Some(generation_expression) => parse_generation_expression(generation_expression),
@@ -260,29 +260,35 @@ pub fn parse_column_key(string: &str) -> ColumnKey {
     }
 }
 
-pub fn parse_column_default(column_default: Option<String>) -> Option<ColumnDefault> {
+pub fn parse_column_default(column_default: Option<String>, extra: &str) -> Option<ColumnDefault> {
     match column_default {
         Some(default) => {
             if !default.is_empty() {
-                if let Ok(int) = default.parse::<i32>() {
-                    Some(ColumnDefault::Int(int))
+                let is_expression = extra == "DEFAULT_GENERATED";
+                let default_value = if let Ok(int) = default.parse::<i32>() {
+                    ColumnDefault::Int(int)
                 } else if let Ok(double) = default.parse::<f64>() {
-                    Some(ColumnDefault::Double(double))
-                } else if default == "CURRENT_DATE" || default == "current_date()" {
-                    Some(ColumnDefault::CurrentDate)
-                } else if default == "CURRENT_TIME" || default == "current_time()" {
-                    Some(ColumnDefault::CurrentTime)
-                } else if default == "CURRENT_TIMESTAMP" || default == "current_timestamp()" {
-                    Some(ColumnDefault::CurrentTimestamp)
+                    ColumnDefault::Double(double)
+                } else if is_expression
+                    && (default == "CURRENT_DATE" || default == "current_date()")
+                {
+                    ColumnDefault::CurrentDate
+                } else if is_expression
+                    && (default == "CURRENT_TIME" || default == "current_time()")
+                {
+                    ColumnDefault::CurrentTime
+                } else if is_expression
+                    && (default == "CURRENT_TIMESTAMP" || default == "current_timestamp()")
+                {
+                    ColumnDefault::CurrentTimestamp
                 } else if default.starts_with('\'') && default.ends_with('\'') {
-                    Some(ColumnDefault::String(
-                        default[1..(default.len() - 1)].into(),
-                    ))
+                    ColumnDefault::String(default[1..(default.len() - 1)].into())
                 } else if default == "NULL" {
                     ColumnDefault::Null
                 } else {
-                    Some(ColumnDefault::String(default))
-                }
+                    ColumnDefault::String(default)
+                };
+                Some(default_value)
             } else {
                 None
             }

From cc51c1dc057b903136ed06a866d8ccb8a45d2548 Mon Sep 17 00:00:00 2001
From: Billy Chan <ccw.billy.123@gmail.com>
Date: Thu, 8 Jun 2023 21:45:13 +0800
Subject: [PATCH 08/17] Customized parsing logic for MySQL and MariaDB column
 default

---
 src/mysql/discovery/mod.rs |   5 +-
 src/mysql/parser/column.rs | 105 +++++++++++++++++++++++++++----------
 2 files changed, 79 insertions(+), 31 deletions(-)

diff --git a/src/mysql/discovery/mod.rs b/src/mysql/discovery/mod.rs
index 8fb36204..d6601ad4 100644
--- a/src/mysql/discovery/mod.rs
+++ b/src/mysql/discovery/mod.rs
@@ -92,7 +92,7 @@ impl SchemaDiscovery {
     pub async fn discover_table(&self, info: TableInfo) -> TableDef {
         let table = SeaRc::new(Alias::new(info.name.as_str()));
         let columns = self
-            .discover_columns(self.schema.clone(), table.clone())
+            .discover_columns(self.schema.clone(), table.clone(), &self.query.system)
             .await;
         let indexes = self
             .discover_indexes(self.schema.clone(), table.clone())
@@ -113,6 +113,7 @@ impl SchemaDiscovery {
         &self,
         schema: SeaRc<dyn Iden>,
         table: SeaRc<dyn Iden>,
+        system: &SystemInfo,
     ) -> Vec<ColumnInfo> {
         let rows = self
             .executor
@@ -124,7 +125,7 @@ impl SchemaDiscovery {
             .map(|row| {
                 let result: ColumnQueryResult = row.into();
                 debug_print!("{:?}", result);
-                let column = result.parse();
+                let column = result.parse(system);
                 debug_print!("{:?}", column);
                 column
             })
diff --git a/src/mysql/parser/column.rs b/src/mysql/parser/column.rs
index 16073e62..d245f513 100644
--- a/src/mysql/parser/column.rs
+++ b/src/mysql/parser/column.rs
@@ -4,18 +4,20 @@ use crate::{parser::Parser, Name};
 use sea_query::{EscapeBuilder, MysqlQueryBuilder};
 
 impl ColumnQueryResult {
-    pub fn parse(self) -> ColumnInfo {
-        parse_column_query_result(self)
+    pub fn parse(self, system: &SystemInfo) -> ColumnInfo {
+        parse_column_query_result(self, system)
     }
 }
 
-pub fn parse_column_query_result(result: ColumnQueryResult) -> ColumnInfo {
+pub fn parse_column_query_result(result: ColumnQueryResult, system: &SystemInfo) -> ColumnInfo {
+    let col_type = parse_column_type(&mut Parser::new(&result.column_type));
+    let default = parse_column_default(&col_type, result.column_default, &result.extra, system);
     ColumnInfo {
         name: result.column_name,
-        col_type: parse_column_type(&mut Parser::new(&result.column_type)),
+        col_type,
         null: parse_column_null(&result.is_nullable),
         key: parse_column_key(&result.column_key),
-        default: parse_column_default(result.column_default, &result.extra),
+        default,
         extra: parse_column_extra(&mut Parser::new(&result.extra)),
         expression: match result.generation_expression {
             Some(generation_expression) => parse_generation_expression(generation_expression),
@@ -260,33 +262,21 @@ pub fn parse_column_key(string: &str) -> ColumnKey {
     }
 }
 
-pub fn parse_column_default(column_default: Option<String>, extra: &str) -> Option<ColumnDefault> {
-    match column_default {
+pub fn parse_column_default(
+    col_type: &Type,
+    default: Option<String>,
+    extra: &str,
+    system: &SystemInfo,
+) -> Option<ColumnDefault> {
+    match default {
         Some(default) => {
             if !default.is_empty() {
-                let is_expression = extra == "DEFAULT_GENERATED";
-                let default_value = if let Ok(int) = default.parse::<i32>() {
-                    ColumnDefault::Int(int)
-                } else if let Ok(double) = default.parse::<f64>() {
-                    ColumnDefault::Double(double)
-                } else if is_expression
-                    && (default == "CURRENT_DATE" || default == "current_date()")
-                {
-                    ColumnDefault::CurrentDate
-                } else if is_expression
-                    && (default == "CURRENT_TIME" || default == "current_time()")
-                {
-                    ColumnDefault::CurrentTime
-                } else if is_expression
-                    && (default == "CURRENT_TIMESTAMP" || default == "current_timestamp()")
-                {
-                    ColumnDefault::CurrentTimestamp
-                } else if default.starts_with('\'') && default.ends_with('\'') {
-                    ColumnDefault::String(default[1..(default.len() - 1)].into())
-                } else if default == "NULL" {
-                    ColumnDefault::Null
+                let default_value = if system.is_mysql() && system.version >= 80000 {
+                    parse_mysql_8_default(default, extra)
+                } else if system.is_maria_db() && system.version >= 100201 {
+                    parse_mariadb_10_default(default)
                 } else {
-                    ColumnDefault::String(default)
+                    parse_mysql_5_default(default, col_type)
                 };
                 Some(default_value)
             } else {
@@ -297,6 +287,63 @@ pub fn parse_column_default(column_default: Option<String>, extra: &str) -> Opti
     }
 }
 
+pub fn parse_mysql_5_default(default: String, col_type: &Type) -> ColumnDefault {
+    let is_date_time_col = matches!(
+        col_type,
+        Type::Date | Type::DateTime(_) | Type::Timestamp(_)
+    );
+    if is_date_time_col && default == "CURRENT_DATE" {
+        ColumnDefault::CurrentDate
+    } else if is_date_time_col && default == "CURRENT_TIME" {
+        ColumnDefault::CurrentTime
+    } else if is_date_time_col && default == "CURRENT_TIMESTAMP" {
+        ColumnDefault::CurrentTimestamp
+    } else if let Ok(int) = default.parse::<i32>() {
+        ColumnDefault::Int(int)
+    } else if let Ok(double) = default.parse::<f64>() {
+        ColumnDefault::Double(double)
+    } else {
+        ColumnDefault::String(default)
+    }
+}
+
+pub fn parse_mysql_8_default(default: String, extra: &str) -> ColumnDefault {
+    let is_expression = extra == "DEFAULT_GENERATED";
+    if is_expression && default == "CURRENT_DATE" {
+        ColumnDefault::CurrentDate
+    } else if is_expression && default == "CURRENT_TIME" {
+        ColumnDefault::CurrentTime
+    } else if is_expression && default == "CURRENT_TIMESTAMP" {
+        ColumnDefault::CurrentTimestamp
+    } else if let Ok(int) = default.parse::<i32>() {
+        ColumnDefault::Int(int)
+    } else if let Ok(double) = default.parse::<f64>() {
+        ColumnDefault::Double(double)
+    } else {
+        ColumnDefault::String(default)
+    }
+}
+
+pub fn parse_mariadb_10_default(default: String) -> ColumnDefault {
+    if default.starts_with('\'') && default.ends_with('\'') {
+        ColumnDefault::String(default[1..(default.len() - 1)].into())
+    } else if let Ok(int) = default.parse::<i32>() {
+        ColumnDefault::Int(int)
+    } else if let Ok(double) = default.parse::<f64>() {
+        ColumnDefault::Double(double)
+    } else if default == "current_date()" {
+        ColumnDefault::CurrentDate
+    } else if default == "current_time()" {
+        ColumnDefault::CurrentTime
+    } else if default == "current_timestamp()" {
+        ColumnDefault::CurrentTimestamp
+    } else if default == "NULL" {
+        ColumnDefault::Null
+    } else {
+        ColumnDefault::String(default)
+    }
+}
+
 pub fn parse_generation_expression(string: String) -> Option<ColumnExpression> {
     if string.is_empty() {
         None

From fca3ee59229ed09ba35772631a06bb0977cf5955 Mon Sep 17 00:00:00 2001
From: Billy Chan <ccw.billy.123@gmail.com>
Date: Fri, 9 Jun 2023 15:08:50 +0800
Subject: [PATCH 09/17] Remove current date and time from `ColumnDefault`

---
 src/mysql/def/column.rs    |  2 --
 src/mysql/parser/column.rs | 21 +++------------------
 src/mysql/writer/column.rs |  2 --
 3 files changed, 3 insertions(+), 22 deletions(-)

diff --git a/src/mysql/def/column.rs b/src/mysql/def/column.rs
index f0bbaaa0..e0ffb0f3 100644
--- a/src/mysql/def/column.rs
+++ b/src/mysql/def/column.rs
@@ -46,8 +46,6 @@ pub enum ColumnDefault {
     Double(f64),
     String(String),
     Null,
-    CurrentDate,
-    CurrentTime,
     CurrentTimestamp,
 }
 
diff --git a/src/mysql/parser/column.rs b/src/mysql/parser/column.rs
index d245f513..dc3126bb 100644
--- a/src/mysql/parser/column.rs
+++ b/src/mysql/parser/column.rs
@@ -288,15 +288,8 @@ pub fn parse_column_default(
 }
 
 pub fn parse_mysql_5_default(default: String, col_type: &Type) -> ColumnDefault {
-    let is_date_time_col = matches!(
-        col_type,
-        Type::Date | Type::DateTime(_) | Type::Timestamp(_)
-    );
-    if is_date_time_col && default == "CURRENT_DATE" {
-        ColumnDefault::CurrentDate
-    } else if is_date_time_col && default == "CURRENT_TIME" {
-        ColumnDefault::CurrentTime
-    } else if is_date_time_col && default == "CURRENT_TIMESTAMP" {
+    let is_date_time_col = matches!(col_type, Type::Timestamp(_));
+    if is_date_time_col && default == "CURRENT_TIMESTAMP" {
         ColumnDefault::CurrentTimestamp
     } else if let Ok(int) = default.parse::<i32>() {
         ColumnDefault::Int(int)
@@ -309,11 +302,7 @@ pub fn parse_mysql_5_default(default: String, col_type: &Type) -> ColumnDefault
 
 pub fn parse_mysql_8_default(default: String, extra: &str) -> ColumnDefault {
     let is_expression = extra == "DEFAULT_GENERATED";
-    if is_expression && default == "CURRENT_DATE" {
-        ColumnDefault::CurrentDate
-    } else if is_expression && default == "CURRENT_TIME" {
-        ColumnDefault::CurrentTime
-    } else if is_expression && default == "CURRENT_TIMESTAMP" {
+    if is_expression && default == "CURRENT_TIMESTAMP" {
         ColumnDefault::CurrentTimestamp
     } else if let Ok(int) = default.parse::<i32>() {
         ColumnDefault::Int(int)
@@ -331,10 +320,6 @@ pub fn parse_mariadb_10_default(default: String) -> ColumnDefault {
         ColumnDefault::Int(int)
     } else if let Ok(double) = default.parse::<f64>() {
         ColumnDefault::Double(double)
-    } else if default == "current_date()" {
-        ColumnDefault::CurrentDate
-    } else if default == "current_time()" {
-        ColumnDefault::CurrentTime
     } else if default == "current_timestamp()" {
         ColumnDefault::CurrentTimestamp
     } else if default == "NULL" {
diff --git a/src/mysql/writer/column.rs b/src/mysql/writer/column.rs
index b3d18402..d3640eef 100644
--- a/src/mysql/writer/column.rs
+++ b/src/mysql/writer/column.rs
@@ -22,8 +22,6 @@ impl ColumnInfo {
                 ColumnDefault::Double(double) => (*double).into(),
                 ColumnDefault::String(string) => string.into(),
                 ColumnDefault::Null => Option::<bool>::None.into(),
-                ColumnDefault::CurrentDate => Keyword::CurrentDate.into(),
-                ColumnDefault::CurrentTime => Keyword::CurrentTime.into(),
                 ColumnDefault::CurrentTimestamp => Keyword::CurrentTimestamp.into(),
             };
             col_def.default(default_expr);

From 880b70d91cebef776506c246a942514166e81930 Mon Sep 17 00:00:00 2001
From: Billy Chan <ccw.billy.123@gmail.com>
Date: Fri, 9 Jun 2023 15:13:06 +0800
Subject: [PATCH 10/17] Add `ColumnDefault::CustomExpr`

---
 src/mysql/def/column.rs | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/mysql/def/column.rs b/src/mysql/def/column.rs
index e0ffb0f3..603d5a7c 100644
--- a/src/mysql/def/column.rs
+++ b/src/mysql/def/column.rs
@@ -45,6 +45,7 @@ pub enum ColumnDefault {
     Int(i32),
     Double(f64),
     String(String),
+    CustomExpr(String),
     Null,
     CurrentTimestamp,
 }

From 51e6b4090da83e3893336717f9daf8c10f75a9f4 Mon Sep 17 00:00:00 2001
From: Billy Chan <ccw.billy.123@gmail.com>
Date: Fri, 9 Jun 2023 15:13:36 +0800
Subject: [PATCH 11/17] Simplify

---
 src/mysql/parser/column.rs | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/mysql/parser/column.rs b/src/mysql/parser/column.rs
index dc3126bb..280a1f6f 100644
--- a/src/mysql/parser/column.rs
+++ b/src/mysql/parser/column.rs
@@ -288,8 +288,7 @@ pub fn parse_column_default(
 }
 
 pub fn parse_mysql_5_default(default: String, col_type: &Type) -> ColumnDefault {
-    let is_date_time_col = matches!(col_type, Type::Timestamp(_));
-    if is_date_time_col && default == "CURRENT_TIMESTAMP" {
+    if matches!(col_type, Type::Timestamp(_)) && default == "CURRENT_TIMESTAMP" {
         ColumnDefault::CurrentTimestamp
     } else if let Ok(int) = default.parse::<i32>() {
         ColumnDefault::Int(int)

From 146c081ee17e55c5350b3919dc09a1fcf1f47d25 Mon Sep 17 00:00:00 2001
From: Billy Chan <ccw.billy.123@gmail.com>
Date: Fri, 9 Jun 2023 15:14:07 +0800
Subject: [PATCH 12/17] Parse custom expression

---
 src/mysql/parser/column.rs | 6 ++++--
 src/mysql/writer/column.rs | 3 ++-
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/src/mysql/parser/column.rs b/src/mysql/parser/column.rs
index 280a1f6f..dc180e7c 100644
--- a/src/mysql/parser/column.rs
+++ b/src/mysql/parser/column.rs
@@ -300,13 +300,15 @@ pub fn parse_mysql_5_default(default: String, col_type: &Type) -> ColumnDefault
 }
 
 pub fn parse_mysql_8_default(default: String, extra: &str) -> ColumnDefault {
-    let is_expression = extra == "DEFAULT_GENERATED";
+    let is_expression = extra.contains("DEFAULT_GENERATED");
     if is_expression && default == "CURRENT_TIMESTAMP" {
         ColumnDefault::CurrentTimestamp
     } else if let Ok(int) = default.parse::<i32>() {
         ColumnDefault::Int(int)
     } else if let Ok(double) = default.parse::<f64>() {
         ColumnDefault::Double(double)
+    } else if is_expression {
+        ColumnDefault::CustomExpr(default)
     } else {
         ColumnDefault::String(default)
     }
@@ -324,7 +326,7 @@ pub fn parse_mariadb_10_default(default: String) -> ColumnDefault {
     } else if default == "NULL" {
         ColumnDefault::Null
     } else {
-        ColumnDefault::String(default)
+        ColumnDefault::CustomExpr(default)
     }
 }
 
diff --git a/src/mysql/writer/column.rs b/src/mysql/writer/column.rs
index d3640eef..57e5ff84 100644
--- a/src/mysql/writer/column.rs
+++ b/src/mysql/writer/column.rs
@@ -1,7 +1,7 @@
 use crate::mysql::def::{CharSet, ColumnDefault, ColumnInfo, NumericAttr, StringAttr, Type};
 use sea_query::{
     Alias, BlobSize, ColumnDef, DynIden, EscapeBuilder, Iden, IntoIden, Keyword, MysqlQueryBuilder,
-    SimpleExpr,
+    SimpleExpr, Expr,
 };
 use std::fmt::Write;
 
@@ -21,6 +21,7 @@ impl ColumnInfo {
                 ColumnDefault::Int(int) => (*int).into(),
                 ColumnDefault::Double(double) => (*double).into(),
                 ColumnDefault::String(string) => string.into(),
+                ColumnDefault::CustomExpr(string) => Expr::cust(string),
                 ColumnDefault::Null => Option::<bool>::None.into(),
                 ColumnDefault::CurrentTimestamp => Keyword::CurrentTimestamp.into(),
             };

From b078079733a77650901390b86d9489cf45c3c96c Mon Sep 17 00:00:00 2001
From: Billy Chan <ccw.billy.123@gmail.com>
Date: Fri, 9 Jun 2023 15:15:42 +0800
Subject: [PATCH 13/17] fmt

---
 src/mysql/writer/column.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/mysql/writer/column.rs b/src/mysql/writer/column.rs
index 57e5ff84..f5a1104a 100644
--- a/src/mysql/writer/column.rs
+++ b/src/mysql/writer/column.rs
@@ -1,7 +1,7 @@
 use crate::mysql::def::{CharSet, ColumnDefault, ColumnInfo, NumericAttr, StringAttr, Type};
 use sea_query::{
-    Alias, BlobSize, ColumnDef, DynIden, EscapeBuilder, Iden, IntoIden, Keyword, MysqlQueryBuilder,
-    SimpleExpr, Expr,
+    Alias, BlobSize, ColumnDef, DynIden, EscapeBuilder, Expr, Iden, IntoIden, Keyword,
+    MysqlQueryBuilder, SimpleExpr,
 };
 use std::fmt::Write;
 

From f11b494230985fb028166755f69de86a056d3a39 Mon Sep 17 00:00:00 2001
From: Billy Chan <ccw.billy.123@gmail.com>
Date: Fri, 9 Jun 2023 15:23:17 +0800
Subject: [PATCH 14/17] Fix

---
 src/mysql/parser/column.rs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/mysql/parser/column.rs b/src/mysql/parser/column.rs
index dc180e7c..07177b1f 100644
--- a/src/mysql/parser/column.rs
+++ b/src/mysql/parser/column.rs
@@ -288,7 +288,8 @@ pub fn parse_column_default(
 }
 
 pub fn parse_mysql_5_default(default: String, col_type: &Type) -> ColumnDefault {
-    if matches!(col_type, Type::Timestamp(_)) && default == "CURRENT_TIMESTAMP" {
+    let is_date_time = matches!(col_type, Type::DateTime(_) | Type::Timestamp(_));
+    if is_date_time && default == "CURRENT_TIMESTAMP" {
         ColumnDefault::CurrentTimestamp
     } else if let Ok(int) = default.parse::<i32>() {
         ColumnDefault::Int(int)

From ae0d2d11bd8ea48639349373d56b4b6140be1f7d Mon Sep 17 00:00:00 2001
From: Chris Tsang <chris.2y3@outlook.com>
Date: Sun, 11 Jun 2023 01:10:56 +0800
Subject: [PATCH 15/17] use i64

---
 src/mysql/def/column.rs    |  6 +++---
 src/mysql/parser/column.rs | 12 ++++++------
 src/mysql/writer/column.rs |  4 ++--
 3 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/src/mysql/def/column.rs b/src/mysql/def/column.rs
index 603d5a7c..3cddd688 100644
--- a/src/mysql/def/column.rs
+++ b/src/mysql/def/column.rs
@@ -42,11 +42,11 @@ pub enum ColumnKey {
 #[derive(Clone, Debug, PartialEq)]
 #[cfg_attr(feature = "with-serde", derive(Serialize, Deserialize))]
 pub enum ColumnDefault {
-    Int(i32),
-    Double(f64),
+    Null,
+    Int(i64),
+    Real(f64),
     String(String),
     CustomExpr(String),
-    Null,
     CurrentTimestamp,
 }
 
diff --git a/src/mysql/parser/column.rs b/src/mysql/parser/column.rs
index 07177b1f..513e08f7 100644
--- a/src/mysql/parser/column.rs
+++ b/src/mysql/parser/column.rs
@@ -291,10 +291,10 @@ pub fn parse_mysql_5_default(default: String, col_type: &Type) -> ColumnDefault
     let is_date_time = matches!(col_type, Type::DateTime(_) | Type::Timestamp(_));
     if is_date_time && default == "CURRENT_TIMESTAMP" {
         ColumnDefault::CurrentTimestamp
-    } else if let Ok(int) = default.parse::<i32>() {
+    } else if let Ok(int) = default.parse::<i64>() {
         ColumnDefault::Int(int)
     } else if let Ok(double) = default.parse::<f64>() {
-        ColumnDefault::Double(double)
+        ColumnDefault::Real(double)
     } else {
         ColumnDefault::String(default)
     }
@@ -304,10 +304,10 @@ pub fn parse_mysql_8_default(default: String, extra: &str) -> ColumnDefault {
     let is_expression = extra.contains("DEFAULT_GENERATED");
     if is_expression && default == "CURRENT_TIMESTAMP" {
         ColumnDefault::CurrentTimestamp
-    } else if let Ok(int) = default.parse::<i32>() {
+    } else if let Ok(int) = default.parse::<i64>() {
         ColumnDefault::Int(int)
     } else if let Ok(double) = default.parse::<f64>() {
-        ColumnDefault::Double(double)
+        ColumnDefault::Real(double)
     } else if is_expression {
         ColumnDefault::CustomExpr(default)
     } else {
@@ -318,10 +318,10 @@ pub fn parse_mysql_8_default(default: String, extra: &str) -> ColumnDefault {
 pub fn parse_mariadb_10_default(default: String) -> ColumnDefault {
     if default.starts_with('\'') && default.ends_with('\'') {
         ColumnDefault::String(default[1..(default.len() - 1)].into())
-    } else if let Ok(int) = default.parse::<i32>() {
+    } else if let Ok(int) = default.parse::<i64>() {
         ColumnDefault::Int(int)
     } else if let Ok(double) = default.parse::<f64>() {
-        ColumnDefault::Double(double)
+        ColumnDefault::Real(double)
     } else if default == "current_timestamp()" {
         ColumnDefault::CurrentTimestamp
     } else if default == "NULL" {
diff --git a/src/mysql/writer/column.rs b/src/mysql/writer/column.rs
index f5a1104a..7991922e 100644
--- a/src/mysql/writer/column.rs
+++ b/src/mysql/writer/column.rs
@@ -18,11 +18,11 @@ impl ColumnInfo {
         let mut extras = Vec::new();
         if let Some(default) = &self.default {
             let default_expr: SimpleExpr = match default {
+                ColumnDefault::Null => Option::<bool>::None.into(),
                 ColumnDefault::Int(int) => (*int).into(),
-                ColumnDefault::Double(double) => (*double).into(),
+                ColumnDefault::Real(double) => (*double).into(),
                 ColumnDefault::String(string) => string.into(),
                 ColumnDefault::CustomExpr(string) => Expr::cust(string),
-                ColumnDefault::Null => Option::<bool>::None.into(),
                 ColumnDefault::CurrentTimestamp => Keyword::CurrentTimestamp.into(),
             };
             col_def.default(default_expr);

From ad2bc09a86b834658df9b7c6b3895c264437dae4 Mon Sep 17 00:00:00 2001
From: Chris Tsang <chris.2y3@outlook.com>
Date: Sun, 11 Jun 2023 01:39:15 +0800
Subject: [PATCH 16/17] Tweaks

---
 src/mysql/parser/column.rs | 20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/src/mysql/parser/column.rs b/src/mysql/parser/column.rs
index 513e08f7..6bc5eab9 100644
--- a/src/mysql/parser/column.rs
+++ b/src/mysql/parser/column.rs
@@ -291,10 +291,10 @@ pub fn parse_mysql_5_default(default: String, col_type: &Type) -> ColumnDefault
     let is_date_time = matches!(col_type, Type::DateTime(_) | Type::Timestamp(_));
     if is_date_time && default == "CURRENT_TIMESTAMP" {
         ColumnDefault::CurrentTimestamp
-    } else if let Ok(int) = default.parse::<i64>() {
+    } else if let Ok(int) = default.parse() {
         ColumnDefault::Int(int)
-    } else if let Ok(double) = default.parse::<f64>() {
-        ColumnDefault::Real(double)
+    } else if let Ok(real) = default.parse() {
+        ColumnDefault::Real(real)
     } else {
         ColumnDefault::String(default)
     }
@@ -304,10 +304,12 @@ pub fn parse_mysql_8_default(default: String, extra: &str) -> ColumnDefault {
     let is_expression = extra.contains("DEFAULT_GENERATED");
     if is_expression && default == "CURRENT_TIMESTAMP" {
         ColumnDefault::CurrentTimestamp
-    } else if let Ok(int) = default.parse::<i64>() {
+    } else if is_expression && default == "NULL" {
+        ColumnDefault::Null
+    } else if let Ok(int) = default.parse() {
         ColumnDefault::Int(int)
-    } else if let Ok(double) = default.parse::<f64>() {
-        ColumnDefault::Real(double)
+    } else if let Ok(real) = default.parse() {
+        ColumnDefault::Real(real)
     } else if is_expression {
         ColumnDefault::CustomExpr(default)
     } else {
@@ -318,10 +320,10 @@ pub fn parse_mysql_8_default(default: String, extra: &str) -> ColumnDefault {
 pub fn parse_mariadb_10_default(default: String) -> ColumnDefault {
     if default.starts_with('\'') && default.ends_with('\'') {
         ColumnDefault::String(default[1..(default.len() - 1)].into())
-    } else if let Ok(int) = default.parse::<i64>() {
+    } else if let Ok(int) = default.parse() {
         ColumnDefault::Int(int)
-    } else if let Ok(double) = default.parse::<f64>() {
-        ColumnDefault::Real(double)
+    } else if let Ok(real) = default.parse() {
+        ColumnDefault::Real(real)
     } else if default == "current_timestamp()" {
         ColumnDefault::CurrentTimestamp
     } else if default == "NULL" {

From e9cdd00a680c9052c5b8f3e404681bdf2b644815 Mon Sep 17 00:00:00 2001
From: Chris Tsang <chris.2y3@outlook.com>
Date: Sun, 11 Jun 2023 01:54:15 +0800
Subject: [PATCH 17/17] MariaDB >= 10.2.7

---
 src/mysql/parser/column.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/mysql/parser/column.rs b/src/mysql/parser/column.rs
index 6bc5eab9..f1481f56 100644
--- a/src/mysql/parser/column.rs
+++ b/src/mysql/parser/column.rs
@@ -273,7 +273,7 @@ pub fn parse_column_default(
             if !default.is_empty() {
                 let default_value = if system.is_mysql() && system.version >= 80000 {
                     parse_mysql_8_default(default, extra)
-                } else if system.is_maria_db() && system.version >= 100201 {
+                } else if system.is_maria_db() && system.version >= 100207 {
                     parse_mariadb_10_default(default)
                 } else {
                     parse_mysql_5_default(default, col_type)