Nested folder: Fix for PostgreSQL (#59405)

* Nested Folders: Fix PostgreSQL LastInsertId failure

* Fix children sorting

* Fix store tests

pkg/services/sqlstore/session.go

@@ -3,12 +3,14 @@ package sqlstore
 import (
 	"context"
 	"errors"
+	"fmt"
 	"reflect"
 	"time"
 
 	"xorm.io/xorm"
 
 	"github.com/grafana/grafana/pkg/infra/log"
+	"github.com/grafana/grafana/pkg/services/sqlstore/migrator"
 	"github.com/grafana/grafana/pkg/util/errutil"
 	"github.com/grafana/grafana/pkg/util/retryer"
 	"github.com/mattn/go-sqlite3"
@@ -131,6 +133,28 @@ func (sess *DBSession) InsertId(bean interface{}) (int64, error) {
 	return id, nil
 }
 
+func (sess *DBSession) WithReturningID(driverName string, query string, args []interface{}) (int64, error) {
+	supported := driverName != migrator.Postgres
+	var id int64
+	if !supported {
+		query = fmt.Sprintf("%s RETURNING id", query)
+		if _, err := sess.SQL(query, args...).Get(&id); err != nil {
+			return id, err
+		}
+	} else {
+		sqlOrArgs := append([]interface{}{query}, args...)
+		res, err := sess.Exec(sqlOrArgs...)
+		if err != nil {
+			return id, err
+		}
+		id, err = res.LastInsertId()
+		if err != nil {
+			return id, err
+		}
+	}
+	return id, nil
+}
+
 func getTypeName(bean interface{}) (res string) {
 	t := reflect.TypeOf(bean)
 	for t.Kind() == reflect.Ptr {