Fix query with Joins

main_test.go

@@ -425,21 +425,35 @@ func TestGroup(t *testing.T) {
 }
 
 func TestJoins(t *testing.T) {
+	var user = User{
+		Name:   "joins",
+		Emails: []Email{{Email: "join1@example.com"}, {Email: "join2@example.com"}},
+	}
+	DB.Save(&user)
+
+	var result User
+	DB.Joins("left join emails on emails.user_id = users.id").Where("name = ?", "joins").First(&result)
+	if result.Name != "joins" || result.Id != user.Id {
+		t.Errorf("Should find all two emails with Join")
+	}
+}
+
+func TestJoinsWithSelect(t *testing.T) {
 	type result struct {
 		Name  string
 		Email string
 	}
 
 	user := User{
-		Name:   "joins",
+		Name:   "joins_with_select",
 		Emails: []Email{{Email: "join1@example.com"}, {Email: "join2@example.com"}},
 	}
 	DB.Save(&user)
 
 	var results []result
-	DB.Table("users").Select("name, email").Joins("left join emails on emails.user_id = users.id").Where("name = ?", "joins").Scan(&results)
+	DB.Table("users").Select("name, email").Joins("left join emails on emails.user_id = users.id").Where("name = ?", "joins_with_select").Scan(&results)
 	if len(results) != 2 || results[0].Email != "join1@example.com" || results[1].Email != "join2@example.com" {
-		t.Errorf("Should find all two emails with Join")
+		t.Errorf("Should find all two emails with Join select")
 	}
 }
 

preload.go

@@ -209,7 +209,7 @@ func (scope *Scope) handleHasManyToManyPreload(field *Field, conditions []interf
 		sourceKeys = append(sourceKeys, key.DBName)
 	}
 
-	db := scope.NewDB().Table(scope.New(reflect.New(destType).Interface()).TableName())
+	db := scope.NewDB().Table(scope.New(reflect.New(destType).Interface()).TableName()).Select("*")
 	preloadJoinDB := joinTableHandler.JoinWith(joinTableHandler, db, scope.Value)
 	if len(conditions) > 0 {
 		preloadJoinDB = preloadJoinDB.Where(conditions[0], conditions[1:]...)

scope_private.go

@@ -213,6 +213,9 @@ var hasCountRegexp = regexp.MustCompile(`(?i)count(.+)`)
 
 func (scope *Scope) selectSql() string {
 	if len(scope.Search.selects) == 0 {
+		if scope.Search.joins != "" {
+			return fmt.Sprintf("%v.*", scope.QuotedTableName())
+		}
 		return "*"
 	}
 	sql := scope.buildSelectQuery(scope.Search.selects)