executor: fix bad null error handling for insert statement when disab…

…ling the strict SQL mode (#10161) (#10254)

executor/executor.go

@@ -1290,8 +1290,11 @@ func ResetContextOfStmt(ctx sessionctx.Context, s ast.StmtNode) (err error) {
 		sc.Priority = stmt.Priority
 	case *ast.InsertStmt:
 		sc.InInsertStmt = true
+		// For insert statement (not for update statement), disabling the StrictSQLMode
+		// should make TruncateAsWarning and DividedByZeroAsWarning,
+		// but should not make DupKeyAsWarning or BadNullAsWarning,
 		sc.DupKeyAsWarning = stmt.IgnoreErr
-		sc.BadNullAsWarning = !vars.StrictSQLMode || stmt.IgnoreErr
+		sc.BadNullAsWarning = stmt.IgnoreErr
 		sc.TruncateAsWarning = !vars.StrictSQLMode || stmt.IgnoreErr
 		sc.DividedByZeroAsWarning = !vars.StrictSQLMode || stmt.IgnoreErr
 		sc.AllowInvalidDate = vars.SQLMode.HasAllowInvalidDatesMode()

executor/executor_test.go

@@ -1764,8 +1764,15 @@ func (s *testSuite) TestSQLMode(c *C) {
 
 	tk.MustExec("set sql_mode = ''")
 	tk.MustExec("insert t values ()")
+	tk.MustQuery("show warnings").Check(testkit.Rows("Warning 1364 Field 'a' doesn't have a default value"))
+	_, err = tk.Exec("insert t values (null)")
+	c.Check(err, NotNil)
+	tk.MustExec("insert ignore t values (null)")
+	tk.MustQuery("show warnings").Check(testkit.Rows("Warning 1048 Column 'a' cannot be null"))
+	tk.MustExec("insert t select null")
+	tk.MustQuery("show warnings").Check(testkit.Rows("Warning 1048 Column 'a' cannot be null"))
 	tk.MustExec("insert t values (1000)")
-	tk.MustQuery("select * from t").Check(testkit.Rows("0", "127"))
+	tk.MustQuery("select * from t order by a").Check(testkit.Rows("0", "0", "0", "127"))
 
 	tk.MustExec("insert tdouble values (10.23)")
 	tk.MustQuery("select * from tdouble").Check(testkit.Rows("9.99"))

executor/insert_common.go

@@ -302,6 +302,10 @@ func (e *InsertValues) insertRowsFromSelect(ctx context.Context, exec func(rows
 	rows := make([][]types.Datum, 0, chk.Capacity())
 
 	sessVars := e.ctx.GetSessionVars()
+	if !sessVars.StrictSQLMode {
+		// If StrictSQLMode is disabled and it is a insert-select statement, it also handle BadNullAsWarning.
+		sessVars.StmtCtx.BadNullAsWarning = true
+	}
 	batchInsert := (sessVars.BatchInsert && !sessVars.InTxn()) || config.GetGlobalConfig().EnableBatchDML
 
 	for {

executor/write_test.go

@@ -679,6 +679,11 @@ commit;`
 	tk.MustExec(`INSERT IGNORE t1 VALUES (1, 1) ON DUPLICATE KEY UPDATE f2 = null;`)
 	tk.MustQuery("show warnings").Check(testkit.Rows("Warning 1048 Column 'f2' cannot be null"))
 	tk.MustQuery(`SELECT * FROM t1 order by f1;`).Check(testkit.Rows("1 0", "2 2"))
+
+	tk.MustExec(`SET sql_mode='';`)
+	_, err = tk.Exec(`INSERT t1 VALUES (1, 1) ON DUPLICATE KEY UPDATE f2 = null;`)
+	c.Assert(err, NotNil)
+	tk.MustQuery(`SELECT * FROM t1 order by f1;`).Check(testkit.Rows("1 0", "2 2"))
 }
 
 func (s *testSuite) TestInsertIgnoreOnDup(c *C) {

table/column.go

@@ -426,12 +426,17 @@ func getColDefaultValueFromNil(ctx sessionctx.Context, col *model.ColumnInfo) (t
 	if col.IsGenerated() {
 		return types.Datum{}, nil
 	}
-	sc := ctx.GetSessionVars().StmtCtx
+	vars := ctx.GetSessionVars()
+	sc := vars.StmtCtx
 	if sc.BadNullAsWarning {
 		sc.AppendWarning(ErrColumnCantNull.GenWithStackByArgs(col.Name))
 		return GetZeroValue(col), nil
 	}
-	return types.Datum{}, ErrNoDefaultValue.GenWithStack("Field '%s' doesn't have a default value", col.Name)
+	if !vars.StrictSQLMode {
+		sc.AppendWarning(ErrNoDefaultValue.GenWithStackByArgs(col.Name))
+		return GetZeroValue(col), nil
+	}
+	return types.Datum{}, ErrNoDefaultValue.GenWithStackByArgs(col.Name)
 }
 
 // GetZeroValue gets zero value for given column type.

table/table.go

@@ -58,7 +58,7 @@ var (
 
 	// ErrNoDefaultValue is used when insert a row, the column value is not given, and the column has not null flag
 	// and it doesn't have a default value.
-	ErrNoDefaultValue = terror.ClassTable.New(codeNoDefaultValue, "field doesn't have a default value")
+	ErrNoDefaultValue = terror.ClassTable.New(codeNoDefaultValue, mysql.MySQLErrName[mysql.ErrNoDefaultForField])
 	// ErrIndexOutBound returns for index column offset out of bound.
 	ErrIndexOutBound = terror.ClassTable.New(codeIndexOutBound, "index column offset out of bound")
 	// ErrUnsupportedOp returns for unsupported operation.
@@ -199,7 +199,7 @@ const (
 	codeColumnCantNull     = mysql.ErrBadNull
 	codeUnknownColumn      = 1054
 	codeDuplicateColumn    = 1110
-	codeNoDefaultValue     = 1364
+	codeNoDefaultValue     = mysql.ErrNoDefaultForField
 	codeTruncateWrongValue = 1366
 	// MySQL error code, "Trigger creation context of table `%-.64s`.`%-.64s` is invalid".
 	// It may happen when inserting some data outside of all table partitions.