Merge pull request #111 from fangrenfu/patch-1

修正mssql 删除数据时错误

library/think/db/builder/Sqlsrv.php

@@ -20,6 +20,7 @@ class Sqlsrv extends Builder
 {
     protected $selectSql = 'SELECT T1.* FROM (SELECT thinkphp.*, ROW_NUMBER() OVER (%ORDER%) AS ROW_NUMBER FROM (SELECT %DISTINCT% %FIELD% FROM %TABLE%%JOIN%%WHERE%%GROUP%%HAVING%) AS thinkphp) AS T1 %LIMIT%%COMMENT%';
     protected $updateSql = 'UPDATE %TABLE% SET %SET% %JOIN% %WHERE% %LIMIT% %LOCK%%COMMENT%';
+    protected $deleteSql = 'DELETE FROM %TABLE% %USING% %JOIN% %WHERE% %LIMIT% %LOCK%%COMMENT%';
 
     /**
      * order分析