[xc]feat:support field INTERVAL YEAR TO MONTH (pingcap#58)

Co-authored-by: crazycs520 <[email protected]>
Reviewed-on: https://git.pingcap.net/pingkai/tidb/pulls/58
Co-authored-by: Zhou Fan <[email protected]>
Co-committed-by: Zhou Fan <[email protected]>

Author: Zhou Fan

pkg/ddl/add_column.go

@@ -863,7 +863,7 @@ func getDefaultValue(ctx exprctx.BuildContext, col *table.Column, option *ast.Co
 	case mysql.TypeEnum:
 		val, err := getEnumDefaultValue(v, col)
 		return val, false, err
-	case mysql.TypeDuration, mysql.TypeDate:
+	case mysql.TypeDuration, mysql.TypeDate, mysql.TypeIntervalYearToMonth:
 		if v, err = v.ConvertTo(ctx.GetEvalCtx().TypeCtx(), &col.FieldType); err != nil {
 			return "", false, errors.Trace(err)
 		}

pkg/expression/builtin_cast.go

@@ -1562,11 +1562,17 @@ func (b *builtinCastStringAsIntSig) evalInt(ctx EvalContext, row chunk.Row) (res
 	}
 
 	val = strings.TrimSpace(val)
+	if b.tp.GetType() == mysql.TypeIntervalYearToMonth {
+		res, _, err = types.ParseIntervalYearMonth(val, 9)
+		if err != nil {
+			return res, false, err
+		}
+		return res, false, err
+	}
 	isNegative := false
 	if len(val) > 1 && val[0] == '-' { // negative number
 		isNegative = true
 	}
-
 	var ures uint64
 	tc := typeCtx(ctx)
 	if !isNegative {

pkg/parser/mysql/const.go

@@ -338,6 +338,9 @@ var DefaultLengthOfMysqlTypes = map[byte]int{
 	TypeEnum:   2,
 	TypeString: 1,
 	TypeSet:    8,
+
+	// a temp value
+	TypeIntervalYearToMonth: 3,
 }
 
 // DefaultLengthOfTimeFraction is the map for default physical length of time fractions.

pkg/parser/mysql/type.go

@@ -46,7 +46,9 @@ const (
 	TypeString     byte = 0xfe /* TypeString is char type */
 	TypeGeometry   byte = 0xff
 
-	TypeTiDBVectorFloat32 byte = 0xe1
+	TypeTiDBVectorFloat32   byte = 0xe1
+	TypeIntervalYearToMonth byte = 0xa1
+	TypeIntervalDayToSecond byte = 0xa2
 )
 
 // Flag information.