SQL语句先前写的时候,很容易把一些特殊的用法忘记,我特此整理了一下SQL语句操作。 :zdEq")v
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一、基础 +Edzjf~Tt
1、说明:创建数据库 /gz:zThf{
CREATE DATABASE database-name #?{qlgv<p
2、说明:删除数据库 MA\m[h]
drop database dbname =)I"wR"v$
3、说明:备份sql server 90/vJN
--- 创建 备份数据的 device S!;LF4VA
USE master B< |VeU
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' mC i[Ps
--- 开始 备份 .u1X+P7
BACKUP DATABASE pubs TO testBack ]~-*hOcQ4
4、说明:创建新表 x\hWyY6J[
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) '>j<yaD'
根据已有的表创建新表: v6s\Z\v)Q`
A:create table tab_new like tab_old (使用旧表创建新表) :qKF58W
B:create table tab_new as select col1,col2... from tab_old definition only }q% jO
5、说明:删除新表 2_;]
drop table tabname HH)"]E5
6、说明:增加一个列 KRYcCn
Alter table tabname add column col type Q}kfM^i
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 Ji;SY{~kv
7、说明:添加主键: Alter table tabname add primary key(col) M[, D *
说明:删除主键: Alter table tabname drop primary key(col) kdp%
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8、说明:创建索引:create [unique] index idxname on tabname(col....) ^=EjadVQ
删除索引:drop index idxname 5|ic3
注:索引是不可更改的,想更改必须删除重新建。 *'D=1{WZ!
9、说明:创建视图:create view viewname as select statement qM%O
删除视图:drop view viewname ddsUz1%l
10、说明:几个简单的基本的sql语句 c=6ahX}d
选择:select * from table1 where 范围 t|}O.u-&;~
插入:insert into table1(field1,field2) values(value1,value2) FigR1/3o'6
删除:delete from table1 where 范围 EYL]TeS
更新:update table1 set field1=value1 where 范围 \PpXL*.
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! KP3n^
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排序:select * from table1 order by field1,field2 [desc] x97L6!
总数:select count as totalcount from table1 Lf. 1>s
求和:select sum(field1) as sumvalue from table1 CSL#s^4T
平均:select avg(field1) as avgvalue from table1 gv#4#]
最大:select max(field1) as maxvalue from table1 Ia2(Km
最小:select min(field1) as minvalue from table1 mN;+TN'?{
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11、说明:几个高级查询运算词 mwh{ "FL(
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A: UNION 运算符 \m4T3fy
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 '-vE%U@<
B: EXCEPT 运算符 .WvlaPK
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 P z ?m>>#
C: INTERSECT 运算符 38~PWKt
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 %}q.cV
注:使用运算词的几个查询结果行必须是一致的。 @6 /yu>%
12、说明:使用外连接 xCWz\-;
A、left outer join: A\z`c
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左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 {Oj7
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c |uI?ySF
B:right outer join: =m7H)z)i*J
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 _%y4q%#
C:full outer join: k[\a)WcY8
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 o#>a 5
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二、提升 $5AC1g'
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) c%z'xM
法一:select * into b from a where 1<>1 8d!GZgC8R
法二:select top 0 * into b from a Qzqc .T
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) a+`D'?z
insert into b(a, b, c) select d,e,f from b; BkawL,
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) 3JO]f5
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 }aF
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. jk*tL8?i
4、说明:子查询(表名1:a 表名2:b) w{!(r
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) ExVDkt0
5、说明:显示文章、提交人和最后回复时间 tx"LeZZ
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b x)SralWb
6、说明:外连接查询(表名1:a 表名2:b) m:uPEpcU
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 7(bQ}mHl\
7、说明:在线视图查询(表名1:a ) K R, z^9
select * from (SELECT a,b,c FROM a) T where t.a > 1; O0T/#<Cn!
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 ~`qEWvPn
select * from table1 where time between time1 and time2 |7"$ w%2
select a,b,c, from table1 where a not between 数值1 and 数值2 @PI%FV z~p
9、说明:in 的使用方法 fRB5U'
select * from table1 where a [not] in ('值1','值2','值4','值6') bFY~oa%C
10、说明:两张关联表,删除主表中已经在副表中没有的信息 5G[x }4U
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) xCXQ<77
11、说明:四表联查问题: Ooc\1lX
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... tIc 7:th
12、说明:日程安排提前五分钟提醒 PT'MNH
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 >oGiIYq
13、说明:一条sql 语句搞定数据库分页 _V2xA88
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 c6&Q^p|CF
14、说明:前10条记录 "?3`
select top 10 * form table1 where 范围 !E2W\chi
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) ` qUX.
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) o.m:3!RW
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 B(_WZa!
(select a from tableA ) except (select a from tableB) except (select a from tableC) k()$:-V
17、说明:随机取出10条数据 0|c}p([~
select top 10 * from tablename order by newid() f>2MI4nMG
18、说明:随机选择记录 wM~H(=s`D
select newid() wi_'iv
19、说明:删除重复记录 SmhGZ
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) I9?Ec6a_
20、说明:列出数据库里所有的表名 Vi*e@IP/
select name from sysobjects where type='U' 8R/dA<Ww
21、说明:列出表里的所有的 3BG>Y(v
select name from syscolumns where id=object_id('TableName') E{?au]y$J
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 t$J.+} }I
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type 3B0PGvCI1
显示结果: cA)[XpQ:+W
type vender pcs oDn|2Sdqd
电脑 A 1 TP%+.#Fu
电脑 A 1 .fAv*pUzU
光盘 B 2 M}O}:1Par
光盘 A 2 E{E0Z9t7&
手机 B 3 t)f-mQz)
手机 C 3 !cSq+eD
23、说明:初始化表table1 q{0R=jb
TRUNCATE TABLE table1 :|+Qe e
24、说明:选择从10到15的记录 oD9^ID+
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc $pyOn2}
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三、技巧 &V7M}@
1、1=1,1=2的使用,在SQL语句组合时用的较多 pO7Zs
"where 1=1" 是表示选择全部 "where 1=2"全部不选, n]}W``=7
如: l12{fpm
if @strWhere !='' z^<L(/rg9"
begin bN$r k|
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 3^?ZG^V
end A9BX_9}]
else ,m_WR7!$E
begin ZfrVjUB
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' A A^{B
end 2ZcKK8X;7
我们可以直接写成 zK|i='XSf
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere PjKECN
2、收缩数据库 ^r6!l.
--重建索引 [F!Y%Zp
DBCC REINDEX w[tmCn+
DBCC INDEXDEFRAG }e2VY
--收缩数据和日志 vS\Nd1~ ?
DBCC SHRINKDB SAYLG
DBCC SHRINKFILE ZJPmR/OV_
3、压缩数据库 ^ D%FX!$
dbcc shrinkdatabase(dbname) ziPR>iz-
4、转移数据库给新用户以已存在用户权限 ",6M)3{|c
exec sp_change_users_login 'update_one','newname','oldname' #>lG7Ns|4
go #J (~_%Wi
5、检查备份集 JN+_|`
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' jhu 07HX_
6、修复数据库 NIdZ
ALTER DATABASE [dvbbs] SET SINGLE_USER El\%E"Tk%
GO =X\^J
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK &>d:R_Q]
GO >NYW{(j
ALTER DATABASE [dvbbs] SET MULTI_USER wX >*H
GO
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7、日志清除 ~5FW[_
SET NOCOUNT ON 4}+/F}TbJ5
DECLARE @LogicalFileName sysname, Od f[*
@MaxMinutes INT, 7xRl9
@NewSize INT &xRo^iV?
USE tablename -- 要操作的数据库名 Q></`QWpoB
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 L:XC
@MaxMinutes = 10, -- Limit on time allowed to wrap log. X+UJzR90
@NewSize = 1 -- 你想设定的日志文件的大小(M) *na?n2Yzt
-- Setup / initialize A,sr[Pa@
DECLARE @OriginalSize int V |(H|9
SELECT @OriginalSize = size .<@8gNm3
FROM sysfiles #@<9S{F
WHERE name = @LogicalFileName [8tL"G6s
SELECT 'Original Size of ' + db_name() + ' LOG is ' + ^[:p|U2mA
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 1-lu\"H`
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' nRyU]=-X
FROM sysfiles n]E?3UGD@W
WHERE name = @LogicalFileName Cj~'Lhmv'T
CREATE TABLE DummyTrans }=c85f~i
(DummyColumn char (8000) not null) {~Rk2:gx
DECLARE @Counter INT, aDO!
@StartTime DATETIME, y=?)n\f
@TruncLog VARCHAR(255) ;>n,:355L
SELECT @StartTime = GETDATE(), AGLscf.
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' [w%
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DBCC SHRINKFILE (@LogicalFileName, @NewSize) M#(+c_(r
EXEC (@TruncLog) |{CfWSB7~@
-- Wrap the log if necessary. 8Z(Mvq]f&
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired :q#Xq;Wp
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) :Nofp&
AND (@OriginalSize * 8 /1024) > @NewSize phM>.y_
BEGIN -- Outer loop. |*}4 m'c
SELECT @Counter = 0 BD(Z5+EU1
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) uEX!xx?Q#
BEGIN -- update JvY}-}?c
INSERT DummyTrans VALUES ('Fill Log') H$y-8-&)
DELETE DummyTrans 0`^&9nR
SELECT @Counter = @Counter + 1 |JQQU!x
END 293M\5:
EXEC (@TruncLog) o!)3?
END On?p 9^9
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 8-2cRs
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + =Xo
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CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' h*- Pr8
FROM sysfiles 6I%5Q4Ll
WHERE name = @LogicalFileName euC&0Ee2
DROP TABLE DummyTrans O#F4WWF
SET NOCOUNT OFF j KoG7HH
8、说明:更改某个表 V$ps>
exec sp_changeobjectowner 'tablename','dbo' -3Hy*1A.
9、存储更改全部表 ZpnxecJUJ
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch Za1QC;7
@OldOwner as NVARCHAR(128), K*~0"F>"0
@NewOwner as NVARCHAR(128) cXKjrL[b
AS p,eTY[k?
DECLARE @Name as NVARCHAR(128) $m/)FnU/
DECLARE @Owner as NVARCHAR(128) ' ~8KSF*!p
DECLARE @OwnerName as NVARCHAR(128) 0N$v"uX@
DECLARE curObject CURSOR FOR 9b9$GyI
select 'Name' = name, ME*LHr,
'Owner' = user_name(uid) >k (C
from sysobjects N<XNTf
where user_name(uid)=@OldOwner E"5*Ei)^3
order by name MRdduPrM%$
OPEN curObject ,%M$0poKM
FETCH NEXT FROM curObject INTO @Name, @Owner mWsI}2
WHILE(@@FETCH_STATUS=0) [k/@E+;
BEGIN z*a:L} $
if @Owner=@OldOwner 2+e}*&iQpp
begin nCdR EXw
set @OwnerName = @OldOwner + '.' + rtrim(@Name) V=o
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exec sp_changeobjectowner @OwnerName, @NewOwner h-`}L=
end ]?!mS[X
-- select @name,@NewOwner,@OldOwner a ?)NC
FETCH NEXT FROM curObject INTO @Name, @Owner AJF#Aw `o
END 2Eu`u!jhx
close curObject uC(V
deallocate curObject %-1O.Q|f
GO Y2~nBb
10、SQL SERVER中直接循环写入数据 gcl5jB5)>
declare @i int @X#F3;
set @i=1 }f6HYU
while @i<30 oY H^_V
begin R8a3
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insert into test (userid) values(@i) .nx2";oi
set @i=@i+1 ` 2V19s]
end oYm[V<nIl
小记存储过程中经常用到的本周,本月,本年函数 nH[yJGZYSA
Dateadd(wk,datediff(wk,0,getdate()),-1) pSdI/Vj'=
Dateadd(wk,datediff(wk,0,getdate()),6) H _zo1AW
Dateadd(mm,datediff(mm,0,getdate()),0) D=-SO
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Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) X:nN0p #
Dateadd(yy,datediff(yy,0,getdate()),0) SC)g^E#
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) Yfzl%wc
上面的SQL代码只是一个时间段 Ju1D
=b
Dateadd(wk,datediff(wk,0,getdate()),-1) @~"h62=]
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Dateadd(wk,datediff(wk,0,getdate()),6) ).`1+b
就是表示本周时间段. jK& h~)
下面的SQL的条件部分,就是查询时间段在本周范围内的: 5>D>% iaHv
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) Q7jb'y$ozO
而在存储过程中 h7lDHIQf
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) "hH.#5j
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) l~w2B>i)