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。 2kVp_=c
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一、基础 i5VG2S
1、说明:创建数据库 06jMj26!
CREATE DATABASE database-name GQ[pG{_+
2、说明:删除数据库 =LK}9ViH
drop database dbname V~[:*WOX
3、说明:备份sql server L1{T
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--- 创建 备份数据的 device aHC%19UN
USE master 9T?64t<Ju
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 5uttv:@=
--- 开始 备份 'bPk'pj9
BACKUP DATABASE pubs TO testBack wFb@1ae\
4、说明:创建新表 2f^-~dz
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) +9C;<f
根据已有的表创建新表: Z\' wm'
A:create table tab_new like tab_old (使用旧表创建新表) PtqGX=u
B:create table tab_new as select col1,col2... from tab_old definition only Oy%Im8.-A#
5、说明:删除新表 :!']p2B
drop table tabname :~D];m
6、说明:增加一个列 U!0E_J
Alter table tabname add column col type ;_N"Fdl
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。 :3 y_mf>
7、说明:添加主键: Alter table tabname add primary key(col) nj
说明:删除主键: Alter table tabname drop primary key(col) E(;i>
8、说明:创建索引:create [unique] index idxname on tabname(col....) ??(Kwtx{
删除索引:drop index idxname qv uxhz F
注:索引是不可更改的,想更改必须删除重新建。 &[~[~m|
9、说明:创建视图:create view viewname as select statement # 66e@
删除视图:drop view viewname >XnO&hW
10、说明:几个简单的基本的sql语句 Um\0i;7 ~4
选择:select * from table1 where 范围 ;ctU&`
插入:insert into table1(field1,field2) values(value1,value2) ;cLUnsB\
删除:delete from table1 where 范围 6__K#r
更新:update table1 set field1=value1 where 范围 i.M2E$b|
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! G0/>8_Q>Nr
排序:select * from table1 order by field1,field2 [desc] !oGQ8 e
总数:select count as totalcount from table1 ?+\E3}:
求和:select sum(field1) as sumvalue from table1 ($SLb6
平均:select avg(field1) as avgvalue from table1 { *$9,
最大:select max(field1) as maxvalue from table1 i-.c=M
最小:select min(field1) as minvalue from table1 N~| t!G*9
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11、说明:几个高级查询运算词 !W~<q{VTs
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A: UNION 运算符 ) Fx?%
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 3e
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B: EXCEPT 运算符 uy9!qk
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 3Oiy)f@{TF
C: INTERSECT 运算符 11{y}J
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 !^L-T?y.2
注:使用运算词的几个查询结果行必须是一致的。 )*D'csGc
12、说明:使用外连接 +v-LL*fa
A、left outer join: |!}wF}iLc)
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 pX_b6%yX(
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c !DcX8~~@
B:right outer join: +$,dwyI2t
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。 gt@SuX!@{^
C:full outer join: Q1T@oxV
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。 HTR1)b
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二、提升 Bm}iU~(Z`
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) R&Ci/
法一:select * into b from a where 1<>1 .[(P
法二:select top 0 * into b from a TY6
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2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) +NR n0
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insert into b(a, b, c) select d,e,f from b; * <q4S(l
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) K(OaW)j
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 Y 1y E
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. l#xw.2bo
4、说明:子查询(表名1:a 表名2:b) ^Plc}W7h
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) m[rL\](-
5、说明:显示文章、提交人和最后回复时间 eEP(
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select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b P7r4ePtLk{
6、说明:外连接查询(表名1:a 表名2:b) $
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select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 8W,*eke?
7、说明:在线视图查询(表名1:a ) ox4W$YdMG
select * from (SELECT a,b,c FROM a) T where t.a > 1; C0<YH "
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 U&Ab#m;
select * from table1 where time between time1 and time2 |^iA6)Q
select a,b,c, from table1 where a not between 数值1 and 数值2 y\z > /q
9、说明:in 的使用方法 6#|qg*OS
select * from table1 where a [not] in ('值1','值2','值4','值6') 41}/w3Z4
10、说明:两张关联表,删除主表中已经在副表中没有的信息 DxfMqH[vs
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ls @5^g
11、说明:四表联查问题: ANb"oX c
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... N9`97;.X
12、说明:日程安排提前五分钟提醒 }p{;^B
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 *8UYS A~v
13、说明:一条sql 语句搞定数据库分页 yoU2AMH2D^
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 OoM_q/oI
14、说明:前10条记录 c[:Wf<%|
select top 10 * form table1 where 范围 t:T?7-XIE
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) Nb1J ~v
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) =YHt9fb$c
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 j ug'g
(select a from tableA ) except (select a from tableB) except (select a from tableC) j+Zt.KXjT
17、说明:随机取出10条数据 >BJ}U_ck
select top 10 * from tablename order by newid() |D<+X^0'
18、说明:随机选择记录 *l-`<.
select newid() m^A]+G#/
19、说明:删除重复记录 )Mi'(C;
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) `
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20、说明:列出数据库里所有的表名 U`1l8'W}:#
select name from sysobjects where type='U' 4+Ti7p06&\
21、说明:列出表里的所有的 blp=Hk
select name from syscolumns where id=object_id('TableName') BKZ v9
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。 .YC;zn^
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 d$[8w/5Of
显示结果: BSDk9Oc
type vender pcs 7E\gxQ(vU
电脑 A 1 WgPgG0VJE
电脑 A 1 u~}%1
光盘 B 2 _:%U_U
光盘 A 2 !0Nf9
手机 B 3 Mj'lASI
手机 C 3 HamEIL-l.
23、说明:初始化表table1 4#h?Wga
TRUNCATE TABLE table1 +5-fk>o
24、说明:选择从10到15的记录 ZpWu,1
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc i@6wO?Tv
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三、技巧 ymkR!
1、1=1,1=2的使用,在SQL语句组合时用的较多 o8tS
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 0[9I0YBJ
如: Mr.JLW
if @strWhere !='' L$}g3{
begin LU(%K{9
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere }$:#+
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end u<kD}
else 9v$qrM`8
begin <soj&f+
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' PI63RH8e
end H
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我们可以直接写成
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere MHl^/e@
2、收缩数据库 eE9|F/-L
--重建索引 N5KEa]k1nw
DBCC REINDEX ^K.*.|
DBCC INDEXDEFRAG gn`zy9PU
--收缩数据和日志 ls]H6z*q
DBCC SHRINKDB a[ i>;0
DBCC SHRINKFILE Xl?YBZ}
3、压缩数据库 Y-]YDXrPQ
dbcc shrinkdatabase(dbname) e`AUYli"
4、转移数据库给新用户以已存在用户权限 fkG##!
exec sp_change_users_login 'update_one','newname','oldname' 4,zvFH*AH
go }!=U^A)
5、检查备份集 97 S? ;T
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' '=@r7g.2
6、修复数据库 H+R7X71{
ALTER DATABASE [dvbbs] SET SINGLE_USER yZ~b+=UM
GO ;Z4o{(/zU
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK AWL[zixR
GO ~v\hIm3=m
ALTER DATABASE [dvbbs] SET MULTI_USER s ^3[W0hL
GO oXbI5XY)wb
7、日志清除 3G.r-
SET NOCOUNT ON avy=0Jmj
DECLARE @LogicalFileName sysname, J&_3VKrN
@MaxMinutes INT, Jh^8xI,`C
@NewSize INT [-]A^?yBM
USE tablename -- 要操作的数据库名 _25d%Ne0
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 pI5_Hg
@MaxMinutes = 10, -- Limit on time allowed to wrap log. hb<k]-'!
@NewSize = 1 -- 你想设定的日志文件的大小(M) ArL-rJ{}
-- Setup / initialize V4EM5 Z\k
DECLARE @OriginalSize int E\iJP^n
SELECT @OriginalSize = size |K)p]i+
FROM sysfiles 5A,=vE
WHERE name = @LogicalFileName 3`ml;
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SELECT 'Original Size of ' + db_name() + ' LOG is ' + j[H0SBKC
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + Ge0Lb+<G
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' =1/q)b,p)
FROM sysfiles zv@bI~3~
WHERE name = @LogicalFileName U3N(cFXn
CREATE TABLE DummyTrans Th/{x
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(DummyColumn char (8000) not null) ,02w@we5
DECLARE @Counter INT,
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@StartTime DATETIME, W]@6=OpH
@TruncLog VARCHAR(255) )^";BVY
SELECT @StartTime = GETDATE(), (M8hy4Ex
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' B5
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DBCC SHRINKFILE (@LogicalFileName, @NewSize) Br&^09S
EXEC (@TruncLog) T*R{L
-- Wrap the log if necessary. sxk*$jO[]
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired :Dj#VN
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ;le0QA
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AND (@OriginalSize * 8 /1024) > @NewSize c(E,&{+E
BEGIN -- Outer loop. /:KQAM0
SELECT @Counter = 0 tJz^DXqAc
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ]'e AO
BEGIN -- update sNf
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INSERT DummyTrans VALUES ('Fill Log') ZqFUPHc
DELETE DummyTrans ?lyltAxs'
SELECT @Counter = @Counter + 1 8J):\jAZ6
END *V -ds8AQ
EXEC (@TruncLog) `$M
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END mV%h[~-
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ]Ly8s#<g]N
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + D Kq-C%
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ? osfL
FROM sysfiles %b9fW
WHERE name = @LogicalFileName ]xYa yN!n
DROP TABLE DummyTrans X+%u(>>
SET NOCOUNT OFF T(gg>_'jh
8、说明:更改某个表 %:%MUdl6
exec sp_changeobjectowner 'tablename','dbo' 4ODX5If
9、存储更改全部表 cP J7E
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch T1bFxim#b
@OldOwner as NVARCHAR(128), pW7kj&a_.
@NewOwner as NVARCHAR(128) G\):2Qz!|
AS (Wn
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DECLARE @Name as NVARCHAR(128) l<Lz{)OR
DECLARE @Owner as NVARCHAR(128) ?l>e75V%w
DECLARE @OwnerName as NVARCHAR(128) Y!aLf[x]
DECLARE curObject CURSOR FOR wM0E%6
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select 'Name' = name, Wkww&Y
'Owner' = user_name(uid) Bqp&2zg)@
from sysobjects w0X$rl1
where user_name(uid)=@OldOwner >R#9\/s
order by name Stt* 1gT
OPEN curObject MorW\7-}
FETCH NEXT FROM curObject INTO @Name, @Owner }`#Bf
WHILE(@@FETCH_STATUS=0) t+J)dr
BEGIN zG<0CZQ8
if @Owner=@OldOwner "!^c
begin 'cYQ?;
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ze
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exec sp_changeobjectowner @OwnerName, @NewOwner tbY SK
end =:;YTie
-- select @name,@NewOwner,@OldOwner RpjSTV8Tkm
FETCH NEXT FROM curObject INTO @Name, @Owner pb6 Q?QG,
END Z+Xc1W^
close curObject M",];h(I6(
deallocate curObject 1-/4Y5?}
GO Y6+k9$h
10、SQL SERVER中直接循环写入数据 N:d
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declare @i int PJ}[D.elO
set @i=1 \k4M{h6
while @i<30 tfsh!)u?
begin &`m~o/
insert into test (userid) values(@i)
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set @i=@i+1 ea>[BB3#
end wD}EW
小记存储过程中经常用到的本周,本月,本年函数 _m" ^lo
Dateadd(wk,datediff(wk,0,getdate()),-1) 4sI3(z)9H
Dateadd(wk,datediff(wk,0,getdate()),6) x)d2G6x
Dateadd(mm,datediff(mm,0,getdate()),0) |KTpK(6p
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) yTP[,bM
Dateadd(yy,datediff(yy,0,getdate()),0) 2=Jmi?k
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 7f[8ED[4
上面的SQL代码只是一个时间段 z(#=tC|
Dateadd(wk,datediff(wk,0,getdate()),-1) [rc'/@L
Dateadd(wk,datediff(wk,0,getdate()),6) UJ
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就是表示本周时间段. 0:s8o@}
下面的SQL的条件部分,就是查询时间段在本周范围内的: g:;Ya?5N
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) !\3}R25
而在存储过程中 Qf"6PJ
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) s!NisF
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) `I@)<d