expression: fix week func format

expression/builtin_time.go

@@ -19,6 +19,7 @@ package expression
 
 import (
 	"fmt"
+	"github.com/pingcap/tidb/sessionctx/variable"
 	"math"
 	"regexp"
 	"strconv"
@@ -1285,7 +1286,16 @@ func (b *builtinWeekWithoutModeSig) evalInt(row chunk.Row) (int64, bool, error)
 		return 0, true, handleInvalidTimeError(b.ctx, types.ErrIncorrectDatetimeValue.GenWithStackByArgs(date.String()))
 	}
 
-	week := date.Time.Week(0)
+	mode := 0
+	modeStr, ok := b.ctx.GetSessionVars().GetSystemVar(variable.DefaultWeekFormat)
+	if ok {
+		mode, err = strconv.Atoi(modeStr)
+		if err != nil {
+			return 0, true, handleInvalidTimeError(b.ctx, types.ErrInvalidWeekModeFormat.GenWithStackByArgs(modeStr))
+		}
+	}
+
+	week := date.Time.Week(mode)
 	return int64(week), false, nil
 }
 

expression/errors.go

@@ -68,7 +68,8 @@ func init() {
 
 // handleInvalidTimeError reports error or warning depend on the context.
 func handleInvalidTimeError(ctx sessionctx.Context, err error) error {
-	if err == nil || !(terror.ErrorEqual(err, types.ErrInvalidTimeFormat) || types.ErrIncorrectDatetimeValue.Equal(err) || types.ErrTruncatedWrongValue.Equal(err)) {
+	if err == nil || !(terror.ErrorEqual(err, types.ErrInvalidTimeFormat) || types.ErrIncorrectDatetimeValue.Equal(err) ||
+		types.ErrTruncatedWrongValue.Equal(err) || types.ErrInvalidWeekModeFormat.Equal(err)) {
 		return err
 	}
 	sc := ctx.GetSessionVars().StmtCtx

types/time.go

@@ -33,6 +33,7 @@ import (
 // Portable analogs of some common call errors.
 var (
 	ErrInvalidTimeFormat      = terror.ClassTypes.New(mysql.ErrTruncatedWrongValue, "invalid time format: '%v'")
+	ErrInvalidWeekModeFormat  = terror.ClassTypes.New(mysql.ErrTruncatedWrongValue, "invalid week mode format: '%v'")
 	ErrInvalidYearFormat      = errors.New("invalid year format")
 	ErrInvalidYear            = errors.New("invalid year")
 	ErrZeroDate               = errors.New("datetime zero in date")