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expr.go
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expr.go
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package squirrel
import (
"bytes"
"database/sql/driver"
"fmt"
"reflect"
"sort"
"strings"
)
const (
// Portable true/false literals.
sqlTrue = "(1=1)"
sqlFalse = "(1=0)"
)
type expr struct {
sql string
args []interface{}
}
// Expr builds an expression from a SQL fragment and arguments.
//
// Ex:
// Expr("FROM_UNIXTIME(?)", t)
func Expr(sql string, args ...interface{}) Sqlizer {
return expr{sql: sql, args: args}
}
func (e expr) ToSql() (sql string, args []interface{}, err error) {
simple := true
for _, arg := range e.args {
if _, ok := arg.(Sqlizer); ok {
simple = false
}
}
if simple {
return e.sql, e.args, nil
}
buf := &bytes.Buffer{}
ap := e.args
sp := e.sql
var isql string
var iargs []interface{}
for err == nil && len(ap) > 0 && len(sp) > 0 {
i := strings.Index(sp, "?")
if i < 0 {
// no more placeholders
break
}
if len(sp) > i+1 && sp[i+1:i+2] == "?" {
// escaped "??"; append it and step past
buf.WriteString(sp[:i+2])
sp = sp[i+2:]
continue
}
if as, ok := ap[0].(Sqlizer); ok {
// sqlizer argument; expand it and append the result
isql, iargs, err = as.ToSql()
buf.WriteString(sp[:i])
buf.WriteString(isql)
args = append(args, iargs...)
} else {
// normal argument; append it and the placeholder
buf.WriteString(sp[:i+1])
args = append(args, ap[0])
}
// step past the argument and placeholder
ap = ap[1:]
sp = sp[i+1:]
}
// append the remaining sql and arguments
buf.WriteString(sp)
return buf.String(), append(args, ap...), err
}
type concatExpr []interface{}
func (ce concatExpr) ToSql() (sql string, args []interface{}, err error) {
for _, part := range ce {
switch p := part.(type) {
case string:
sql += p
case Sqlizer:
pSql, pArgs, err := p.ToSql()
if err != nil {
return "", nil, err
}
sql += pSql
args = append(args, pArgs...)
default:
return "", nil, fmt.Errorf("%#v is not a string or Sqlizer", part)
}
}
return
}
// ConcatExpr builds an expression by concatenating strings and other expressions.
//
// Ex:
// name_expr := Expr("CONCAT(?, ' ', ?)", firstName, lastName)
// ConcatExpr("COALESCE(full_name,", name_expr, ")")
func ConcatExpr(parts ...interface{}) concatExpr {
return concatExpr(parts)
}
// aliasExpr helps to alias part of SQL query generated with underlying "expr"
type aliasExpr struct {
expr Sqlizer
alias string
}
// Alias allows to define alias for column in SelectBuilder. Useful when column is
// defined as complex expression like IF or CASE
// Ex:
// .Column(Alias(caseStmt, "case_column"))
func Alias(expr Sqlizer, alias string) aliasExpr {
return aliasExpr{expr, alias}
}
func (e aliasExpr) ToSql() (sql string, args []interface{}, err error) {
sql, args, err = e.expr.ToSql()
if err == nil {
sql = fmt.Sprintf("(%s) AS %s", sql, e.alias)
}
return
}
// Eq is syntactic sugar for use with Where/Having/Set methods.
type Eq map[string]interface{}
func (eq Eq) toSQL(useNotOpr bool) (sql string, args []interface{}, err error) {
if len(eq) == 0 {
// Empty Sql{} evaluates to true.
sql = sqlTrue
return
}
var (
exprs []string
equalOpr = "="
inOpr = "IN"
nullOpr = "IS"
inEmptyExpr = sqlFalse
)
if useNotOpr {
equalOpr = "<>"
inOpr = "NOT IN"
nullOpr = "IS NOT"
inEmptyExpr = sqlTrue
}
sortedKeys := getSortedKeys(eq)
for _, key := range sortedKeys {
var expr string
val := eq[key]
switch v := val.(type) {
case driver.Valuer:
if val, err = v.Value(); err != nil {
return
}
}
r := reflect.ValueOf(val)
if r.Kind() == reflect.Ptr {
if r.IsNil() {
val = nil
} else {
val = r.Elem().Interface()
}
}
if val == nil {
expr = fmt.Sprintf("%s %s NULL", key, nullOpr)
} else {
if isListType(val) {
valVal := reflect.ValueOf(val)
if valVal.Len() == 0 {
expr = inEmptyExpr
if args == nil {
args = []interface{}{}
}
} else {
for i := 0; i < valVal.Len(); i++ {
args = append(args, valVal.Index(i).Interface())
}
expr = fmt.Sprintf("%s %s (%s)", key, inOpr, Placeholders(valVal.Len()))
}
} else {
expr = fmt.Sprintf("%s %s ?", key, equalOpr)
args = append(args, val)
}
}
exprs = append(exprs, expr)
}
sql = strings.Join(exprs, " AND ")
return
}
func (eq Eq) ToSql() (sql string, args []interface{}, err error) {
return eq.toSQL(false)
}
// NotEq is syntactic sugar for use with Where/Having/Set methods.
// Ex:
// .Where(NotEq{"id": 1}) == "id <> 1"
type NotEq Eq
func (neq NotEq) ToSql() (sql string, args []interface{}, err error) {
return Eq(neq).toSQL(true)
}
// Like is syntactic sugar for use with LIKE conditions.
// Ex:
// .Where(Like{"name": "%irrel"})
type Like map[string]interface{}
func (lk Like) toSql(opr string) (sql string, args []interface{}, err error) {
var exprs []string
for key, val := range lk {
expr := ""
switch v := val.(type) {
case driver.Valuer:
if val, err = v.Value(); err != nil {
return
}
}
if val == nil {
err = fmt.Errorf("cannot use null with like operators")
return
} else {
if isListType(val) {
err = fmt.Errorf("cannot use array or slice with like operators")
return
} else {
expr = fmt.Sprintf("%s %s ?", key, opr)
args = append(args, val)
}
}
exprs = append(exprs, expr)
}
sql = strings.Join(exprs, " AND ")
return
}
func (lk Like) ToSql() (sql string, args []interface{}, err error) {
return lk.toSql("LIKE")
}
// NotLike is syntactic sugar for use with LIKE conditions.
// Ex:
// .Where(NotLike{"name": "%irrel"})
type NotLike Like
func (nlk NotLike) ToSql() (sql string, args []interface{}, err error) {
return Like(nlk).toSql("NOT LIKE")
}
// ILike is syntactic sugar for use with ILIKE conditions.
// Ex:
// .Where(ILike{"name": "sq%"})
type ILike Like
func (ilk ILike) ToSql() (sql string, args []interface{}, err error) {
return Like(ilk).toSql("ILIKE")
}
// NotILike is syntactic sugar for use with ILIKE conditions.
// Ex:
// .Where(NotILike{"name": "sq%"})
type NotILike Like
func (nilk NotILike) ToSql() (sql string, args []interface{}, err error) {
return Like(nilk).toSql("NOT ILIKE")
}
// Lt is syntactic sugar for use with Where/Having/Set methods.
// Ex:
// .Where(Lt{"id": 1})
type Lt map[string]interface{}
func (lt Lt) toSql(opposite, orEq bool) (sql string, args []interface{}, err error) {
var (
exprs []string
opr = "<"
)
if opposite {
opr = ">"
}
if orEq {
opr = fmt.Sprintf("%s%s", opr, "=")
}
sortedKeys := getSortedKeys(lt)
for _, key := range sortedKeys {
var expr string
val := lt[key]
switch v := val.(type) {
case driver.Valuer:
if val, err = v.Value(); err != nil {
return
}
}
if val == nil {
err = fmt.Errorf("cannot use null with less than or greater than operators")
return
}
if isListType(val) {
err = fmt.Errorf("cannot use array or slice with less than or greater than operators")
return
}
expr = fmt.Sprintf("%s %s ?", key, opr)
args = append(args, val)
exprs = append(exprs, expr)
}
sql = strings.Join(exprs, " AND ")
return
}
func (lt Lt) ToSql() (sql string, args []interface{}, err error) {
return lt.toSql(false, false)
}
// LtOrEq is syntactic sugar for use with Where/Having/Set methods.
// Ex:
// .Where(LtOrEq{"id": 1}) == "id <= 1"
type LtOrEq Lt
func (ltOrEq LtOrEq) ToSql() (sql string, args []interface{}, err error) {
return Lt(ltOrEq).toSql(false, true)
}
// Gt is syntactic sugar for use with Where/Having/Set methods.
// Ex:
// .Where(Gt{"id": 1}) == "id > 1"
type Gt Lt
func (gt Gt) ToSql() (sql string, args []interface{}, err error) {
return Lt(gt).toSql(true, false)
}
// GtOrEq is syntactic sugar for use with Where/Having/Set methods.
// Ex:
// .Where(GtOrEq{"id": 1}) == "id >= 1"
type GtOrEq Lt
func (gtOrEq GtOrEq) ToSql() (sql string, args []interface{}, err error) {
return Lt(gtOrEq).toSql(true, true)
}
type conj []Sqlizer
func (c conj) join(sep, defaultExpr string) (sql string, args []interface{}, err error) {
if len(c) == 0 {
return defaultExpr, []interface{}{}, nil
}
var sqlParts []string
for _, sqlizer := range c {
partSQL, partArgs, err := nestedToSql(sqlizer)
if err != nil {
return "", nil, err
}
if partSQL != "" {
sqlParts = append(sqlParts, partSQL)
args = append(args, partArgs...)
}
}
if len(sqlParts) > 0 {
sql = fmt.Sprintf("(%s)", strings.Join(sqlParts, sep))
}
return
}
// And conjunction Sqlizers
type And conj
func (a And) ToSql() (string, []interface{}, error) {
return conj(a).join(" AND ", sqlTrue)
}
// Or conjunction Sqlizers
type Or conj
func (o Or) ToSql() (string, []interface{}, error) {
return conj(o).join(" OR ", sqlFalse)
}
func getSortedKeys(exp map[string]interface{}) []string {
sortedKeys := make([]string, 0, len(exp))
for k := range exp {
sortedKeys = append(sortedKeys, k)
}
sort.Strings(sortedKeys)
return sortedKeys
}
func isListType(val interface{}) bool {
if driver.IsValue(val) {
return false
}
valVal := reflect.ValueOf(val)
return valVal.Kind() == reflect.Array || valVal.Kind() == reflect.Slice
}