sql语句帮助文档. SELECT 从数据库中检索行，并允许从一个或多个表中选择一个或多个行或列。虽然 SELECT 语句的完整语法较复杂，但是其主要的子句可归纳如下： SELECT select_list [ INTO new_table ] FROM table_source [ WHERE search_condition ] [ GROUP BY group_by_expression ] [ HAVING search_condition ] [ ORDER BY order_exp
最近，同事需要从数个表中查询用户的业务和报告数据，写了一个SQL语句，查询比较慢：
Select
S.Name,
S.AccountantCode,
(
Select COUNT(*) from (
Select Distinct BusinessBackupId from Biz_BusinessBackupCustomer where Id in (
Select BusinessBackupCustomerId from Rpt_RegistForm where ( SignatureC
