fix date function

Author: angelamayxie

enginetest/queries/function_queries.go

@@ -2106,12 +2106,28 @@ var FunctionQueryTests = []QueryTest{
 		Expected: []sql.Row{{"0000-01-01"}},
 	},
 	{
-		Query:    "select date('0000-00-00')",
-		Expected: []sql.Row{{"0000-00-00"}},
+		Query:                 "select date('0000-00-00')",
+		Expected:              []sql.Row{{nil}},
+		ExpectedWarning:       mysql.ERTruncatedWrongValue,
+		ExpectedWarningsCount: 1,
+	},
+	{
+		Query:                 "select date(0)",
+		Expected:              []sql.Row{{nil}},
+		ExpectedWarning:       mysql.ERTruncatedWrongValue,
+		ExpectedWarningsCount: 1,
 	},
 	{
-		Query:    "select date(0)",
-		Expected: []sql.Row{{"0000-00-00"}},
+		Query:                 "select date(false)",
+		Expected:              []sql.Row{{nil}},
+		ExpectedWarning:       mysql.ERTruncatedWrongValue,
+		ExpectedWarningsCount: 1,
+	},
+	{
+		Query:                 "select date(true)",
+		Expected:              []sql.Row{{nil}},
+		ExpectedWarning:       mysql.ERTruncatedWrongValue,
+		ExpectedWarningsCount: 1,
 	},
 	{
 		Query:    "select extract(day from 0)",

sql/expression/function/time.go

@@ -1295,20 +1295,26 @@ func (*Date) CollationCoercibility(ctx *sql.Context) (collation sql.CollationID,
 
 // Eval implements the Expression interface.
 func (d *Date) Eval(ctx *sql.Context, row sql.Row) (interface{}, error) {
-	return getDatePart(ctx, d.UnaryExpression, row, func(v interface{}) interface{} {
-		if v == nil {
-			return nil
-		}
+	dateVal, err := d.Child.Eval(ctx, row)
+	if err != nil {
+		return nil, err
+	}
 
-		date, ok := v.(time.Time)
-		if !ok {
-			return nil
-		}
-		if date.Equal(types.ZeroTime) {
-			return types.ZeroDateStr
-		}
-		return date.Format("2006-01-02")
-	})
+	date, err := getDate(ctx, dateVal)
+	if err != nil {
+		return nil, err
+	}
+	if date == nil {
+		return nil, nil
+	}
+
+	dateTime, ok := date.(time.Time)
+	if !ok || dateTime.Equal(types.ZeroTime) {
+		ctx.Warn(1292, "%s", types.ErrConvertingToTime.New(dateVal).Error())
+		return nil, nil
+	}
+
+	return dateTime.Format("2006-01-02"), nil
 }
 
 // WithChildren implements the Expression interface.