add OrderBy() and Limit() in delete

delete.go

@@ -2,20 +2,39 @@ package sqlingo
 
 import (
 	"database/sql"
+	"strconv"
+	"strings"
 )
 
+type deleteStatus struct {
+	scope    scope
+	where    BooleanExpression
+	orderBys []OrderBy
+	limit    *int
+}
+
 type deleteWithTable interface {
 	Where(conditions ...BooleanExpression) deleteWithWhere
 }
 
 type deleteWithWhere interface {
-	GetSQL() (string, error)
-	Execute() (result sql.Result, err error)
+	toDeleteFinal
+	OrderBy(orderBys ...OrderBy) deleteWithOrder
+	Limit(limit int) deleteWithLimit
 }
 
-type deleteStatus struct {
-	scope scope
-	where BooleanExpression
+type deleteWithOrder interface {
+	toDeleteFinal
+	Limit(limit int) deleteWithLimit
+}
+
+type deleteWithLimit interface {
+	toDeleteFinal
+}
+
+type toDeleteFinal interface {
+	GetSQL() (string, error)
+	Execute() (result sql.Result, err error)
 }
 
 func (d *database) DeleteFrom(table Table) deleteWithTable {
@@ -27,14 +46,44 @@ func (s deleteStatus) Where(conditions ...BooleanExpression) deleteWithWhere {
 	return s
 }
 
+func (s deleteStatus) OrderBy(orderBys ...OrderBy) deleteWithOrder {
+	s.orderBys = orderBys
+	return s
+}
+
+func (s deleteStatus) Limit(limit int) deleteWithLimit {
+	s.limit = &limit
+	return s
+}
+
 func (s deleteStatus) GetSQL() (string, error) {
+	var sb strings.Builder
+	sb.Grow(128)
+
+	sb.WriteString("DELETE FROM ")
+	sb.WriteString(s.scope.Tables[0].GetSQL(s.scope))
+	sb.WriteString(" WHERE ")
 	whereSql, err := s.where.GetSQL(s.scope)
 	if err != nil {
 		return "", err
 	}
-	sqlString := "DELETE FROM " + s.scope.Tables[0].GetSQL(s.scope) + " WHERE " + whereSql
+	sb.WriteString(whereSql)
+
+	if len(s.orderBys) > 0 {
+		orderBySql, err := commaOrderBys(s.scope, s.orderBys)
+		if err != nil {
+			return "", err
+		}
+		sb.WriteString(" ORDER BY ")
+		sb.WriteString(orderBySql)
+	}
+
+	if s.limit != nil {
+		sb.WriteString(" LIMIT ")
+		sb.WriteString(strconv.Itoa(*s.limit))
+	}
 
-	return sqlString, nil
+	return sb.String(), nil
 }
 
 func (s deleteStatus) Execute() (sql.Result, error) {

delete_test.go

@@ -20,4 +20,14 @@ func TestDelete(t *testing.T) {
 	if _, err := db.DeleteFrom(Table1).Where(errorExpression).Execute(); err == nil {
 		t.Error("should get error here")
 	}
+
+	if _, err := db.DeleteFrom(Table1).Where(Raw("#1#")).Limit(3).Execute(); err != nil {
+		t.Error(err)
+	}
+	assertLastSql(t, "DELETE FROM `table1` WHERE #1# LIMIT 3")
+
+	if _, err := db.DeleteFrom(Table1).Where(Raw("#1#")).OrderBy(Raw("#2#")).Limit(3).Execute(); err != nil {
+		t.Error(err)
+	}
+	assertLastSql(t, "DELETE FROM `table1` WHERE #1# ORDER BY #2# LIMIT 3")
 }