sqlserver查询表中某列数据类型

select column_name, data_type
from information_schema.columns
where table_name = 'tStu'

查询表中某列不为空的数据

select * from tStu
where comp != '0'

清空表中数据

truncate table tStu

改变某列数据类型

alter table tNum alter column email varchar(40)

表中增加某列

alter table tNum add address varchar(80)

表中增加自增id列

alter table tStu add id int identity(1,1) unique

复制表

select * into tStuNew from tStu

表中插入数据

insert into tNum select * from tStu

查询表中重复数据

select * from tStu where id not in 
(select dt.id from ( select min(id) as id from tStu group by tName) dt)

判断数字字段首位是否为1

select * from tNum where left(tNum.tPho, 1)!='1'

判断手机号格式是否正确

select * from tNum where len([tPho])!=11 
or [tPho] not like '[1][3456789]%'

更改表中某一数据内容

update tStu set tName='cheems' where tAge='12'