ddl: fix the modify column operation on the bit column (#12008) (#…

…16312)
pingcap · Apr 13, 2020 · dc54c5d · dc54c5d
1 parent 3541c0f
commit dc54c5d
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Showing 2 changed files with 8 additions and 5 deletions.
diff --git a/ddl/ddl_api.go b/ddl/ddl_api.go
@@ -579,6 +579,7 @@ func columnDefToCol(ctx sessionctx.Context, offset int, colDef *ast.ColumnDef, o
 		col.Flag &= ^mysql.BinaryFlag
 		col.Flag |= mysql.ZerofillFlag
 	}
+
 	// If you specify ZEROFILL for a numeric column, MySQL automatically adds the UNSIGNED attribute to the column.
 	// See https://dev.mysql.com/doc/refman/5.7/en/numeric-type-overview.html for more details.
 	// But some types like bit and year, won't show its unsigned flag in `show create table`.
@@ -1985,9 +1986,6 @@ func setColumnComment(ctx sessionctx.Context, col *table.Column, option *ast.Col
 
 // setDefaultAndComment is only used in getModifiableColumnJob.
 func setDefaultAndComment(ctx sessionctx.Context, col *table.Column, options []*ast.ColumnOption) error {
-	if len(options) == 0 {
-		return nil
-	}
 	var hasDefaultValue, setOnUpdateNow bool
 	var err error
 	for _, opt := range options {
@@ -2047,6 +2045,10 @@ func setDefaultAndComment(ctx sessionctx.Context, col *table.Column, options []*
 	// it is `not null` and not an `AUTO_INCREMENT` field or `TIMESTAMP` field.
 	setNoDefaultValueFlag(col, hasDefaultValue)
 
+	if col.Tp == mysql.TypeBit {
+		col.Flag |= mysql.UnsignedFlag
+	}
+
 	if hasDefaultValue {
 		return errors.Trace(checkDefaultValue(ctx, col, true))
 	}

diff --git a/executor/ddl_test.go b/executor/ddl_test.go
@@ -253,7 +253,7 @@ func (s *testSuite6) TestAlterTableModifyColumn(c *C) {
 	tk := testkit.NewTestKit(c, s.store)
 	tk.MustExec("use test")
 	tk.MustExec("drop table if exists mc")
-	tk.MustExec("create table mc(c1 int, c2 varchar(10))")
+	tk.MustExec("create table mc(c1 int, c2 varchar(10), c3 bit)")
 	_, err := tk.Exec("alter table mc modify column c1 short")
 	c.Assert(err, NotNil)
 	tk.MustExec("alter table mc modify column c1 bigint")
@@ -266,9 +266,10 @@ func (s *testSuite6) TestAlterTableModifyColumn(c *C) {
 	tk.MustExec("alter table mc modify column c2 varchar(11)")
 	tk.MustExec("alter table mc modify column c2 text(13)")
 	tk.MustExec("alter table mc modify column c2 text")
+	tk.MustExec("alter table mc modify column c3 bit")
 	result := tk.MustQuery("show create table mc")
 	createSQL := result.Rows()[0][1]
-	expected := "CREATE TABLE `mc` (\n  `c1` bigint(20) DEFAULT NULL,\n  `c2` text DEFAULT NULL\n) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin"
+	expected := "CREATE TABLE `mc` (\n  `c1` bigint(20) DEFAULT NULL,\n  `c2` text DEFAULT NULL,\n  `c3` bit(1) DEFAULT NULL\n) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin"
 	c.Assert(createSQL, Equals, expected)
 
 	// test multiple collate modification in column.