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。 ;
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一、基础 l'3pQ;
1、说明:创建数据库 zA1lca0HK
CREATE DATABASE database-name M`l.t -ut
2、说明:删除数据库 *q1% IJ
drop database dbname <^lRUw
3、说明:备份sql server -k"^o!p
--- 创建 备份数据的 device }|XtypbL
USE master #cCL.p"]
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' u5Ftu?t
--- 开始 备份 >2Kh0rIH
BACKUP DATABASE pubs TO testBack VL*ovD%-
4、说明:创建新表 Et/&^&=\-
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) a(0*um(
根据已有的表创建新表: smry2*g
A:create table tab_new like tab_old (使用旧表创建新表) iURk=*Z=
B:create table tab_new as select col1,col2... from tab_old definition only Ck!VV2U#
5、说明:删除新表 +*hm-lv?
drop table tabname G;~V
6、说明:增加一个列 Lg+G; W
Alter table tabname add column col type 4Z/Q=Mq2
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。 l'TWkQ-
7、说明:添加主键: Alter table tabname add primary key(col) \xS&v7b
说明:删除主键: Alter table tabname drop primary key(col) `4~H/'%QB
8、说明:创建索引:create [unique] index idxname on tabname(col....) n;:rf 7hGY
删除索引:drop index idxname oD$J0{K6
注:索引是不可更改的,想更改必须删除重新建。 >`%'4<I
9、说明:创建视图:create view viewname as select statement J;f!!<l\
删除视图:drop view viewname 7IjQi=#:
10、说明:几个简单的基本的sql语句 )-`;1ca)s
选择:select * from table1 where 范围 >J>b>SU=-
插入:insert into table1(field1,field2) values(value1,value2) f?'JAC*
删除:delete from table1 where 范围 wV^V]c ?U
更新:update table1 set field1=value1 where 范围 gR}35:$Z-
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 1)[]x9]^q'
排序:select * from table1 order by field1,field2 [desc] G3{=@Z1
总数:select count as totalcount from table1 1rDqa(7
求和:select sum(field1) as sumvalue from table1 =%>oR
平均:select avg(field1) as avgvalue from table1 57g</p
最大:select max(field1) as maxvalue from table1 aM$W*-Y
最小:select min(field1) as minvalue from table1 6MxKl
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11、说明:几个高级查询运算词 x4/M}%h!;B
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A: UNION 运算符 txPIG/
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 ]TyisaT
B: EXCEPT 运算符 oun;rMq
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 \R3H+W
C: INTERSECT 运算符 78/N
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 *>+,(1Fz
注:使用运算词的几个查询结果行必须是一致的。 E_bO9nRHV
12、说明:使用外连接 Y
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A、left outer join: PxfY&;4n!
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 R?p00
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c {4-[r#R<M
B:right outer join: Yp:KI7
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 ($~RoQ=0S
C:full outer join: ]7/
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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。 @-&s: Qli
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二、提升 HX6Ma{vBk
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) &|`C)6[C
法一:select * into b from a where 1<>1 KR%{a(V;7
法二:select top 0 * into b from a '_$uW&{NI
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) h)Ff2tX
insert into b(a, b, c) select d,e,f from b; wWp(yvz
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) =lVK IW
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 u@4V7;L
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. P(K>=O
4、说明:子查询(表名1:a 表名2:b) MXyaE~LK
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) <fs2fTUeqF
5、说明:显示文章、提交人和最后回复时间 s\P2Bp_{
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b ?Oc{bF7
6、说明:外连接查询(表名1:a 表名2:b) Ck /F9(
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 2~t[RY
7、说明:在线视图查询(表名1:a ) HWVtop/
select * from (SELECT a,b,c FROM a) T where t.a > 1; >N.]|\V
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 -@Uqz781
select * from table1 where time between time1 and time2 \2vg{
select a,b,c, from table1 where a not between 数值1 and 数值2 nO)X!dp}J
9、说明:in 的使用方法 shMSN]S_x
select * from table1 where a [not] in ('值1','值2','值4','值6') A<B=f<N3gV
10、说明:两张关联表,删除主表中已经在副表中没有的信息 7k( Kq5w.
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ?PyG/W
11、说明:四表联查问题: eBJUv]o %
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... k{<,\J
12、说明:日程安排提前五分钟提醒 ;-Jb1"5
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 +/ &_v^sC;
13、说明:一条sql 语句搞定数据库分页 "$}vP<SM
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 "XT"|KF|D
14、说明:前10条记录 qBT.x,$
select top 10 * form table1 where 范围 =ID
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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.) b%Eei2Gm%
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) >B>CB3U
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 BY]i;GVq
(select a from tableA ) except (select a from tableB) except (select a from tableC) np4+"
17、说明:随机取出10条数据 =?-ye!w
select top 10 * from tablename order by newid() k`x=D5s\
18、说明:随机选择记录 YOJ6w
select newid() x1BobhU~Zl
19、说明:删除重复记录 [S@}T
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Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 0{j&6I2
20、说明:列出数据库里所有的表名 o'$jNciOW
select name from sysobjects where type='U' yA3wtm/?
21、说明:列出表里的所有的 8Y#\xzod
select name from syscolumns where id=object_id('TableName') "{D|@Bc
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 h48SItY
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type >pr=|$zk=
显示结果: 36n>jS&
type vender pcs X~xd/M=9^
电脑 A 1 Jx=hJ-FY
电脑 A 1 {Ixg2=E\
光盘 B 2 SKW%X8
光盘 A 2 L-9~uM3@\
手机 B 3 Kb^>-[Yx
手机 C 3 >[1W:KQA
23、说明:初始化表table1 ZlojbL@|4
TRUNCATE TABLE table1 .E@|D6$D
24、说明:选择从10到15的记录 RO3oP1@B
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 5H9r=a
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三、技巧 {vE(l'
1、1=1,1=2的使用,在SQL语句组合时用的较多 aceZ3U>W
"where 1=1" 是表示选择全部 "where 1=2"全部不选, B7Tk4q\;Q
如: Ia'ZV7'
if @strWhere !='' Gxax2o
begin wWXD\{Hk
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 2+Wzf)tB
end `4 y]Z)
else 8#&q$kE
begin $v b,P(
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' W@2vjz
end =-o'gL
我们可以直接写成 W<<9y
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ~RD+.A
2、收缩数据库 aSP4a+\*
--重建索引 YKa0H%B(
DBCC REINDEX kHv[H]+v
DBCC INDEXDEFRAG "p3_y`h6+
--收缩数据和日志 9TAj) {U%'
DBCC SHRINKDB SI6B#u-i
DBCC SHRINKFILE P5gN #G
3、压缩数据库 oW;6h.
dbcc shrinkdatabase(dbname) ]LZ`LL'#Y_
4、转移数据库给新用户以已存在用户权限 k;5P om
exec sp_change_users_login 'update_one','newname','oldname' [0UGuj
go dr<<! q /
5、检查备份集 cc44R|Kr$$
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' O6]. *25
6、修复数据库 {ccIxL
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ALTER DATABASE [dvbbs] SET SINGLE_USER 7_# 1Ec|;
GO 4c+$%pq5
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK
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GO =\{\g7
ALTER DATABASE [dvbbs] SET MULTI_USER Y\=FLO9
GO 6yy;JQAke
7、日志清除 }17.~
SET NOCOUNT ON &Z^l=YH,
DECLARE @LogicalFileName sysname, tV/Z)fpyH
@MaxMinutes INT, IooNb:(
@NewSize INT HWm#t./
USE tablename -- 要操作的数据库名 9GdB#k6W`
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 4m-I5!=O
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 8by@iQ
@NewSize = 1 -- 你想设定的日志文件的大小(M) U,Mx@KdV
-- Setup / initialize D?M!ra
DECLARE @OriginalSize int xE-7P|2
SELECT @OriginalSize = size :h,`8 Di
FROM sysfiles _P?\.W@
WHERE name = @LogicalFileName A%\tiZe
SELECT 'Original Size of ' + db_name() + ' LOG is ' + J`*iZvW#Bx
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + \x>65;
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' O3o: qly!
FROM sysfiles u? fTL2~
WHERE name = @LogicalFileName #?B%Ja%
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CREATE TABLE DummyTrans 26n^Dy>}
(DummyColumn char (8000) not null) UMN*]_'+;b
DECLARE @Counter INT, ,1/}^f6
@StartTime DATETIME, [4J6iF
@TruncLog VARCHAR(255) De_ CF8
SELECT @StartTime = GETDATE(), EC6k{y}bA
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' :"o
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DBCC SHRINKFILE (@LogicalFileName, @NewSize) 4@;-%H&7
EXEC (@TruncLog) @$eT~ C
-- Wrap the log if necessary. _KD5T4FZR
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 4l8BQz}sb
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) GYB+RU}],
AND (@OriginalSize * 8 /1024) > @NewSize +2C?9:bH
BEGIN -- Outer loop. kVS?RHR
SELECT @Counter = 0 Ov82ibp_1
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) #2xSyOrmf
BEGIN -- update ;o<m}bGaT
INSERT DummyTrans VALUES ('Fill Log') Tx%VU8\?n
DELETE DummyTrans 6*@yE
SELECT @Counter = @Counter + 1 Vga-@
END fYrGpW(`
EXEC (@TruncLog) (ozb%a#B
END o5aLUWi-
SELECT 'Final Size of ' + db_name() + ' LOG is ' + c3
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CONVERT(VARCHAR(30),size) + ' 8K pages or ' + SNT5Am z!
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' zX7q:Pt
FROM sysfiles [*m2
WHERE name = @LogicalFileName 1f(DU4h
DROP TABLE DummyTrans k6\^p;!Y
SET NOCOUNT OFF G"y.Z2$
8、说明:更改某个表 PKq-@F%X
exec sp_changeobjectowner 'tablename','dbo' RD<75]**{
9、存储更改全部表 @o e\"vz
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch Z"I/ NGiU
@OldOwner as NVARCHAR(128), MQcr^Y_
@NewOwner as NVARCHAR(128) Z%gx%$
AS >P. 'CU
DECLARE @Name as NVARCHAR(128) R,@g7p
DECLARE @Owner as NVARCHAR(128) %1:c hvS
DECLARE @OwnerName as NVARCHAR(128) 'q%%m/,VPQ
DECLARE curObject CURSOR FOR qI3NkVA'C
select 'Name' = name, G6`J1Uk
'Owner' = user_name(uid) @\Js8[wS9@
from sysobjects +K6szGP
where user_name(uid)=@OldOwner #NRh\Wj|
order by name `^UK
OPEN curObject XT@Mzo49z\
FETCH NEXT FROM curObject INTO @Name, @Owner HT`1E0G8)
WHILE(@@FETCH_STATUS=0) oYM,8 K
BEGIN uL?vG6% ^1
if @Owner=@OldOwner 7]22"mc
begin W$?e<@
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 'qv;sB.
exec sp_changeobjectowner @OwnerName, @NewOwner k<4P6?
end ^O%9yEo
-- select @name,@NewOwner,@OldOwner kB\kpW
FETCH NEXT FROM curObject INTO @Name, @Owner $(HjI
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END CHaE;olo
close curObject 3 EYiQ`
deallocate curObject keqcV23k
GO 6/mF2&&g
10、SQL SERVER中直接循环写入数据 2'{}<9
declare @i int </E>tMW
set @i=1 @%W]".*'}
while @i<30 Yr&Ka:
begin G{c#\?12C
insert into test (userid) values(@i) E,*&BDW
set @i=@i+1 5JFV%odo
end :%-,Fxl4
小记存储过程中经常用到的本周,本月,本年函数 oO=o|w|T
Dateadd(wk,datediff(wk,0,getdate()),-1) 7!2
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Dateadd(wk,datediff(wk,0,getdate()),6) BgRZ<B`
Dateadd(mm,datediff(mm,0,getdate()),0) b1!@v+
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) uMFV%+I
Dateadd(yy,datediff(yy,0,getdate()),0) .gT4_
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) YL^Z4: p
上面的SQL代码只是一个时间段 XizPM N5a
Dateadd(wk,datediff(wk,0,getdate()),-1) V,LVB_6
Dateadd(wk,datediff(wk,0,getdate()),6) m4/}Jx[
就是表示本周时间段. J4yt N3
下面的SQL的条件部分,就是查询时间段在本周范围内的: QB1M3b
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) Q_}/ Pn$1
而在存储过程中 m)f|:MM
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) `mB.pz[
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 4#Eul