parser: split ALTER TABLE ADD COLUMN (#1340) (#1345)

Signed-off-by: ti-srebot <ti-srebot@pingcap.com>

Co-authored-by: lance6716 <lance6716@gmail.com>

pkg/parser/common.go

@@ -271,6 +271,27 @@ func SplitDDL(stmt ast.StmtNode, schema string) (sqls []string, err error) {
 
 			v.Specs = []*ast.AlterTableSpec{spec}
 
+			// handle `alter table t1 add column (c1 int, c2 int)`
+			if spec.Tp == ast.AlterTableAddColumns && len(spec.NewColumns) > 1 {
+				columns := spec.NewColumns
+				spec.Position = &ast.ColumnPosition{
+					Tp: ast.ColumnPositionNone, // otherwise restore will become "alter table t1 add column (c1 int)"
+				}
+				for _, c := range columns {
+					spec.NewColumns = []*ast.ColumnDef{c}
+					bf.Reset()
+					err = stmt.Restore(ctx)
+					if err != nil {
+						v.Specs = specs
+						v.Table = table
+						return nil, terror.ErrRestoreASTNode.Delegate(err)
+					}
+					sqls = append(sqls, bf.String())
+				}
+				// we have restore SQL for every columns, skip below general restoring and continue on next spec
+				continue
+			}
+
 			bf.Reset()
 			err = stmt.Restore(ctx)
 			if err != nil {

pkg/parser/common_test.go

@@ -67,6 +67,7 @@ var sqls = []string{
 	"alter table `t1` partition by list (a) (partition x default)",
 	"alter table `t1` partition by system_time (partition x history, partition y current)",
 	"alter database `test` charset utf8mb4",
+	"alter table `t1` add column (c1 int, c2 int)",
 }
 
 var nonDDLs = []string{
@@ -171,6 +172,7 @@ func (t *testParserSuite) TestResolveDDL(c *C) {
 		{"ALTER TABLE `test`.`t1` PARTITION BY LIST (`a`) (PARTITION `x` DEFAULT)"},
 		{"ALTER TABLE `test`.`t1` PARTITION BY SYSTEM_TIME (PARTITION `x` HISTORY,PARTITION `y` CURRENT)"},
 		{"ALTER DATABASE `test` CHARACTER SET = utf8mb4"},
+		{"ALTER TABLE `test`.`t1` ADD COLUMN `c1` INT", "ALTER TABLE `test`.`t1` ADD COLUMN `c2` INT"},
 	}
 
 	expectedTableName := [][][]*filter.Table{
@@ -215,6 +217,7 @@ func (t *testParserSuite) TestResolveDDL(c *C) {
 		{{genTableName("test", "t1")}},
 		{{genTableName("test", "t1")}},
 		{{genTableName("test", "")}},
+		{{genTableName("test", "t1")}, {genTableName("test", "t1")}},
 	}
 
 	targetTableNames := [][][]*filter.Table{
@@ -259,6 +262,7 @@ func (t *testParserSuite) TestResolveDDL(c *C) {
 		{{genTableName("xtest", "xt1")}},
 		{{genTableName("xtest", "xt1")}},
 		{{genTableName("xtest", "")}},
+		{{genTableName("xtest", "t1")}, {genTableName("xtest", "t1")}},
 	}
 
 	targetSQLs := [][]string{
@@ -303,6 +307,7 @@ func (t *testParserSuite) TestResolveDDL(c *C) {
 		{"ALTER TABLE `xtest`.`xt1` PARTITION BY LIST (`a`) (PARTITION `x` DEFAULT)"},
 		{"ALTER TABLE `xtest`.`xt1` PARTITION BY SYSTEM_TIME (PARTITION `x` HISTORY,PARTITION `y` CURRENT)"},
 		{"ALTER DATABASE `xtest` CHARACTER SET = utf8mb4"},
+		{"ALTER TABLE `xtest`.`t1` ADD COLUMN `c1` INT", "ALTER TABLE `xtest`.`t1` ADD COLUMN `c2` INT"},
 	}
 
 	for i, sql := range sqls {

tests/sequence_safe_mode/data/db1.increment.sql

@@ -1,15 +1,13 @@
 use sequence_safe_mode_test;
 insert into t1 (uid, name) values (10003, 'Buenos Aires');
-alter table t1 add column age int;
+alter table t1 add column (age int, level int);
 alter table t1 add index age(age);
-alter table t1 add column level int;
 alter table t1 add index level(level);
 insert into t1 (uid, name, age) values (10005, 'Buenos Aires', 200);
 insert into t2 (uid, name) values (20005, 'Aureliano José');
 insert into t1 (uid, name, age) values (10006, 'Buenos Aires', 200);
-alter table t2 add column age int;
+alter table t2 add column (age int, level int);
 alter table t2 add index age(age);
-alter table t2 add column level int;
 alter table t2 add index level(level);
 insert into t1 (uid, name, age) values (10007, 'Buenos Aires', 300);
 insert into t2 (uid, name, age) values (20006, 'Colonel Aureliano Buendía', 301);

tests/sequence_safe_mode/data/db2.increment.sql

@@ -1,13 +1,11 @@
 use sequence_safe_mode_test;
 delete from t3 where name = 'Santa Sofía de la Piedad';
-alter table t2 add column age int;
+alter table t2 add column (age int, level int);
 alter table t2 add index age(age);
-alter table t2 add column level int;
 alter table t2 add index level(level);
 insert into t2 (uid, name, age) values (40002, 'Remedios Moscote', 100), (40003, 'Amaranta', 103);
 insert into t3 (uid, name) values (30004, 'Aureliano José'), (30005, 'Santa Sofía de la Piedad'), (30006, '17 Aurelianos');
-alter table t3 add column age int;
+alter table t3 add column (age int, level int);
 alter table t3 add index age(age);
-alter table t3 add column level int;
 alter table t3 add index level(level);
 update t3 set age = 1;