sql 常用语句积累收藏

1．如何删除表中的重复记录？(这里指记录的每个字段都要相同)
select distinct * into #temp from tab
delete tab
insert tab select * from #temp
drop table #temp

2．怎样返回数据库中用户表的表单名
select name from sysobjects where xtype='U'
select name from sysobjects where xtype = 'u' and status >=0

3．返回两个表中共有的所有记录
select * from testTable as a inner join TestTableChild as b on a.id = b.parentid

4．返回两个表里共有的记录,且不重复
select a.id,a.name,b.name from testTable as a inner join TestTableChild as b on a.id = b.parentid group by a.id,a.name,b.name

5．向一个表A中插入记录,并且插入的记录在A中不存在(通过一个字段来判断)
insert into trace_users
(tracekey,muteSMS,CreateTime,traceuser,tracetime,traceSlot,traceduration)
Select 'TRACE_TIMER',0,getdate(),mobileid,getdate(),'30','0' from Epm_EmployeeList where corpid = 10001 and not exists (select traceuser from trace_users ) and mobileid like '13%' and len(mobileid) = 11

6、根据出生日期，算出年龄
DATEDIFF(month, T.Birthday, GETDATE()) AS MONTHS //得到月份
MONTHS /12 取整就是年龄

7、等待时间再执行语句
waitfor delay '00:00:05'
select * from studentinfo
waitfor time ’23:08:00
select * from employee

8、指定值的范围查询
stockname like '[a-zA-Z]%' --------- ([]指定值的范围)

stockname like '[^F-M]%' --------- (^排除指定范围)

9、从表中获取值并插入另一张表中
insert into table2 (a) select a from table1

10、备份与恢复数据库
backup database SCardDB to disk = 'F:/SCardDB.2006年10月10日(105748).bak'
restore database kangda from disk='d:/backup.bak‘

11、对查询结果随机排序
SELECT * FROM Northwind..Orders ORDER BY NEWID()

12、按姓氏笔画排序
Select * From TableName Order By CustomerName Collate Chinese_PRC_Stroke_ci_as

13获取某一个表的所有字段
select name from syscolumns where id=object_id('表名')

14、记录转换
select *,case Type when 1 then '移动' when 2 then '联通' when 3 then '小灵通' end as TypeName from abc

15、按拼音首字母排序
select * from 表名 order by 列名 Collate Chinese_PRC_CS_AS_KS_WS