1、新增字段
ALTER TABLE SubmitReply --表名 ADD GG3 int ---新增的字段名和类型 not null default 0 --默认值 可选参数,无此参数的话就缺省情况默认NULL
2、两个表关联更新
UPDATE B SET B.loginname=c.loginname FROM t_employee A, t_systemuser B, oa_employee c WHERE A.employeeid=B.belonguserid AND A.oaemployeeid = c.id
3、非唯一索引创建和删除
--创建 create index UQ_report_paylog_carNo on report_paylog(carNo) create index UQ_report_checkout_carNo on report_checkout(carNo) create index UQ_report_present_carNo on report_present(carNo) create index UQ_report_present_userType on report_present(userType) --删除 drop index UQ_report_paylog_carNo on report_paylog drop index UQ_report_checkout_carNo on report_checkout drop index UQ_report_present_carNo on report_present drop index UQ_report_present_userType on report_present
--- cross join用法
INSERT INTO [lpn_parkV5].[dbo].[user_permission_detail] ([userId] ,[carNo] ,[channelId] ,[opType] ,[operateTime] ,[downloadFlage] ,[endTime] ,[userType]) select c.userid,c.carno,pc.channelId,0,getdate(),0,u.endtime,u.usertype from user_info u inner join user_car c on u.userid=c.userid cross join park_channel pc where u.usertype='FixNoLimit'
-- sqlserver 中GO 的用法
go代表事务, 用GO分开的 脚本互不影响
--一次性给数据库所有表增加相同字段
select ' alter table '+name+' add [date] datetime ' from sys.tables where type ='U'
--mysql 查询所有表名 并进行相关操作
select CONCAT('delete ', table_name,' where parkcode=506') from information_schema.tables where table_schema='ee_main'
--查询所有字段
select name from syscolumns where id=(select max(id) from sysobjects where xtype='u' and name='表名') --读取指定表的所有列名
--sqlserver 查询所有表和字段的关系
SELECT c.[name] AS 字段名, (select top 1 name from sys.sysTypes tp where c.[system_type_id]=tp.[xtype])+'('+CAST(c.[max_length] as nvarchar(200))+')' as 类型, t.[name] AS 表名, cast(ep.[value] as nvarchar(200)) AS [字段说明] FROM sys.tables AS t INNER JOIN sys.columns AS c ON t.object_id = c.object_id LEFT JOIN sys.extended_properties AS ep ON ep.major_id = c.object_id AND ep.minor_id = c.column_id where t.type='u'
--mysql 查询所有表和字段的关系
select COLUMN_NAME,COLUMN_TYPE,'orders_success',column_comment from INFORMATION_SCHEMA.Columns where table_schema='lpnservice' and table_name='orders_success'