去掉exists 更改为 join,能够避免嵌套子查询,这样会大大提高查询效率。 explain SELECT *FROM my_neighbor n LEFT JOIN my_neighbor_apply sra ON n.id = sra.neighbored AND sra.user_id = 'xxx' INNER JOIN message_info m on n.id = m.neighbor_id AND m.inuser = 'xxx'WHERE n.topic_status < ...
2.多表关联更新时,使用再加上inner join 或 left join等连接,示例如下 UPDATE t_user_bank b SET is_active='是' FROM t_user_arch u INNER JOIN t_deposit d ON u.arch_id=d.arch_id WHERE u.arch_id=b.arch_id and d.balance=0 and u.rec_no='2021090306002' 二、想用多表关联查询并且dele...
FROM pg_class a LEFT OUTERJOIN pg_description bON b.objsubid=0AND a.oid = b.objoid WHERE a.relnamespace = (SELECT oidFROM pg_namespaceWHERE nspname='public')--用户表一般存储在public模式下 AND a.relkind='r' ORDERBY a.relname 使用表名查询表字段的定义 SELECT a.attnum, a.attnameAS...
在表上发出UPDATE、DELETE和INSERT要修改表中数据时会取得这种锁模式。 冲突级别:5,6,7,8 4.ShareUpdateExclusive 一些在线维护类操作所获得的锁,例如VACUUM(不带FULL)、ANALYZE、CREATE INDEX CONCURRENTLY、CREATE STATISTICS、ALTER TABLE VALIDATE等,该锁类型是自排他的。 冲突级别:4,5,6,7,8 5.Share 发出CRE...
SELECT `DictTypeId`,`Value`,`Code`,`OrderNo`,`Remark`,`Status`,`CreateTime`,`UpdateTime`,`CreateUserId`,`UpdateUserId`,`IsDelete`,`Id` FROM `SysDictData` WHERE ( `DictTypeId` = 14544926246725 ) AND ( `IsDelete` = 0 )ORDER BY `OrderNo` ASC【MySQL数据库---异常 2023/10/11 星期...
(建立) conn.Open "Provider = microsoft.ACE.oledb.12.0; Data Source(驱动) =" & link(连接) SQL = "select * from [Excel 12.0( 驱动 );hdr=no( 无标题 );Database=" & ThisWorkbook.FullName & "].[Adjust$k2:m] as a left join [参数] on (a.f1=[参数].[Topcode]) and (a.f2=[...
DELETE, REFERENCES, TRIGGER ON ALL TABLES IN SCHEMA testschema TO testuser ; GRANT EXECUTE ON ALL FUNCTIONS IN SCHEMA testschema TO testuser ; GRANT ALL ON ALL SEQUENCES IN SCHEMA testschema TO testuser ; GRANT USAGE,CREATE ON SCHEMA testschema TO testuser ; GRANT TEMPORARY ON DATABASE te...
LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace WHERE c.relkind IN ('r', 'v', 'm', 'S', 'f') AND n.nspname !~ '^pg_' AND pg_catalog.pg_table_is_visible(c.oid) ORDER BY 1, 2; ``` 得到权限说明如下 ``` Schema | Name | Type | Access privileges ...
The utility functions,http_get(),http_post(),http_put(),http_delete()andhttp_head()are just wrappers around a master function,http(http_request)that returnshttp_response. Theheadersfield for requests and response is a PostgreSQL array of typehttp_headerwhich is just a simple tuple. ...
affected_rows/mysqli_affected_rows()函数返回上一个SELECT、INSERT、UPDATE、REPLACE或DELETE查询中受影响的行数 Syntax:mysqli_affected_rows(connection); 这将返回受影响的行数(可以是0或以上)。此外,-1表示查询返回了错误。 尝试以这种方式更新代码, ...