fix Exist bug when using on MSSQL

session_exist.go

@@ -10,6 +10,7 @@ import (
 	"reflect"
 
 	"github.com/go-xorm/builder"
+	"github.com/xormplus/core"
 )
 
 // Exist returns true if the record exist otherwise return false
@@ -35,10 +36,18 @@ func (session *Session) Exist(bean ...interface{}) (bool, error) {
 					return false, err
 				}
 
-				sqlStr = fmt.Sprintf("SELECT * FROM %s WHERE %s LIMIT 1", tableName, condSQL)
+				if session.engine.dialect.DBType() == core.MSSQL {
+					sqlStr = fmt.Sprintf("SELECT top 1 * FROM %s WHERE %s", tableName, condSQL)
+				} else {
+					sqlStr = fmt.Sprintf("SELECT * FROM %s WHERE %s LIMIT 1", tableName, condSQL)
+				}
 				args = condArgs
 			} else {
-				sqlStr = fmt.Sprintf("SELECT * FROM %s LIMIT 1", tableName)
+				if session.engine.dialect.DBType() == core.MSSQL {
+					sqlStr = fmt.Sprintf("SELECT top 1 * FROM %s", tableName)
+				} else {
+					sqlStr = fmt.Sprintf("SELECT * FROM %s LIMIT 1", tableName)
+				}
 				args = []interface{}{}
 			}
 		} else {