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。 oSoG&4
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一、基础 4o8!p\a
1、说明:创建数据库 8] *{i
CREATE DATABASE database-name ? 6l::M
2、说明:删除数据库 k*Kq:$9"
drop database dbname ajAEGD2Zq
3、说明:备份sql server 2~)]E#9
--- 创建 备份数据的 device Y>+D\|%Q
USE master c#DTL/8"DO
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' )".gjW8{#L
--- 开始 备份 4\?B,!
BACKUP DATABASE pubs TO testBack Fk43sqU6~
4、说明:创建新表 a lR}|ez
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) r4s R5p]|
根据已有的表创建新表: 8z-Td- R6
A:create table tab_new like tab_old (使用旧表创建新表) 83a
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B:create table tab_new as select col1,col2... from tab_old definition only eD3F%wxz
5、说明:删除新表 A@]
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drop table tabname pLU>vQA
6、说明:增加一个列 F\e'z
Alter table tabname add column col type QbWD&8T0O
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 L[K_!^MZ
7、说明:添加主键: Alter table tabname add primary key(col) ){}#v&
说明:删除主键: Alter table tabname drop primary key(col) n7G$gLX
8、说明:创建索引:create [unique] index idxname on tabname(col....) a_yV*N`D
删除索引:drop index idxname [I9d
注:索引是不可更改的,想更改必须删除重新建。 }bVyvH
9、说明:创建视图:create view viewname as select statement *Pl[a1=o
删除视图:drop view viewname ?r+tU
10、说明:几个简单的基本的sql语句 9HE)!Col
选择:select * from table1 where 范围 9`muk
插入:insert into table1(field1,field2) values(value1,value2) ;P_Zen
删除:delete from table1 where 范围 jd{J3s '%
更新:update table1 set field1=value1 where 范围 ]~P?
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! @lX)dY
排序:select * from table1 order by field1,field2 [desc] 9pgct6BO
总数:select count as totalcount from table1 0[];c$r<
求和:select sum(field1) as sumvalue from table1 uFqH_04
平均:select avg(field1) as avgvalue from table1 aE"t['
最大:select max(field1) as maxvalue from table1 Wac8x%J
最小:select min(field1) as minvalue from table1 -=RXhE_{
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11、说明:几个高级查询运算词 z 4-wvn<*
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A: UNION 运算符 #FcYJH
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 CeQcnJU
B: EXCEPT 运算符 X DX_c@U
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 ,'j5tU?c
C: INTERSECT 运算符 ;@L#0
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 ObCwWj^qO
注:使用运算词的几个查询结果行必须是一致的。 38#(ruv
12、说明:使用外连接 bQ)r8[o!
A、left outer join: "@n$(-.
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。 qH
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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 bchhokH
B:right outer join: Di6:r3sEO
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。 iY2bRXA
C:full outer join: Nl+2m4
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。 1/m/Iw@
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二、提升 Q,$x6YwE
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ;i]cmy
法一:select * into b from a where 1<>1 fq(e~Aqw$
法二:select top 0 * into b from a rLnu\X=h$
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) uO6_lOT9n
insert into b(a, b, c) select d,e,f from b; S8y4 p0mV
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) im'0^
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 /[q@=X&
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ,[~EThcq
4、说明:子查询(表名1:a 表名2:b) l^_X?L@
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) `/U:u9H9v
5、说明:显示文章、提交人和最后回复时间 Gc'HF"w
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b !cpBX>{w
6、说明:外连接查询(表名1:a 表名2:b) x83XJFPWL
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c (ZnA#%
7、说明:在线视图查询(表名1:a ) 0nS6<:
select * from (SELECT a,b,c FROM a) T where t.a > 1; IE6/
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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 hYV{N7$U|
select * from table1 where time between time1 and time2 Cfj*[i4
select a,b,c, from table1 where a not between 数值1 and 数值2 J+zqu
9、说明:in 的使用方法 >#ou8}0
select * from table1 where a [not] in ('值1','值2','值4','值6') K5KN}sRs"
10、说明:两张关联表,删除主表中已经在副表中没有的信息 wqyAEVea'8
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ~t}:vGD j
11、说明:四表联查问题: ~ce.&C7cR
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... p|((r?{
12、说明:日程安排提前五分钟提醒 =4[zt^WX"
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 O []+v
13、说明:一条sql 语句搞定数据库分页 _:gV7>S?
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 1$|z%(
14、说明:前10条记录 AL;"S;8
select top 10 * form table1 where 范围 rQWft r^
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.) {ys_uS{c*
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) kO.rgW82
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 ._yr7uY[M
(select a from tableA ) except (select a from tableB) except (select a from tableC) %~h'#S2X(
17、说明:随机取出10条数据 HwcGbbX)
select top 10 * from tablename order by newid() eAqQ~)8^
18、说明:随机选择记录 'e&4#VLH^
select newid() FLWz7Rj
19、说明:删除重复记录 n Au>i<
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) <Z&gAqj 2
20、说明:列出数据库里所有的表名 BoXCc"q[
select name from sysobjects where type='U' fSTEZH
21、说明:列出表里的所有的 nuQ"\ G
select name from syscolumns where id=object_id('TableName') KDhHp^IXQ
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。 M *}$$Fe|
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 =_XcG!"
显示结果: 1#@'U90xf
type vender pcs e7;]+pN]J
电脑 A 1 sJD"u4#y
电脑 A 1 giTlXz3D9
光盘 B 2 |QY+vO7fxj
光盘 A 2 &M2x`
手机 B 3 RBb@@k[v
手机 C 3 sq^,l6es>
23、说明:初始化表table1 A@#dv2JzP
TRUNCATE TABLE table1 0'~?u '
24、说明:选择从10到15的记录 M$GD8|*e
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc Dn@ n:m
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三、技巧 OS,$}I[`8
1、1=1,1=2的使用,在SQL语句组合时用的较多 k >MgrtJI
"where 1=1" 是表示选择全部 "where 1=2"全部不选, H!A^ MI
如: Oe#k|
if @strWhere !='' "Vh(%N`6
begin LU]~d<i99
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere hImCy9i}
end C
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else irm8z|N-
begin eDm,8Se
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ]gEfm~YV
end XyI w5
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我们可以直接写成 A(uN=r@O
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere *qqFIp^
2、收缩数据库 NubD2
--重建索引 :DD4BY
DBCC REINDEX s.~SV"
DBCC INDEXDEFRAG #4hP_Vhc
--收缩数据和日志 4[#.N
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DBCC SHRINKDB ,^[s4
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DBCC SHRINKFILE /j^zHrLN
3、压缩数据库 GZ e
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dbcc shrinkdatabase(dbname) ?=vwr,ir
4、转移数据库给新用户以已存在用户权限 *Dn{MD7,M
exec sp_change_users_login 'update_one','newname','oldname' XkD_SaL}
go sPw(+m*C
5、检查备份集 jlB3BwG{w
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' Ns $PS\
6、修复数据库 LY>JE6zTt
ALTER DATABASE [dvbbs] SET SINGLE_USER /t/q$X
GO E,X,RM~
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DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK p-}:7CXP
GO qkEy$[D9
ALTER DATABASE [dvbbs] SET MULTI_USER iaC$K@a{
GO q8D1MEBL`
7、日志清除 [brrziZ
SET NOCOUNT ON ERZ[t\g)
DECLARE @LogicalFileName sysname, qvscf_%FM
@MaxMinutes INT, '=2t(@aC
@NewSize INT U".-C`4v
USE tablename -- 要操作的数据库名 r~;N(CG
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 Grqs*V &|g
@MaxMinutes = 10, -- Limit on time allowed to wrap log. w"e2}iE7
@NewSize = 1 -- 你想设定的日志文件的大小(M) Xnh1pwDhe<
-- Setup / initialize w5;EnI
DECLARE @OriginalSize int Z`%;bP:
SELECT @OriginalSize = size e`oc#Od&x]
FROM sysfiles p<jr&zVEc>
WHERE name = @LogicalFileName -7`J(f.rYC
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 4{R`
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + }lY-_y
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' j Hzy1P{?
FROM sysfiles `3OGCy
WHERE name = @LogicalFileName
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CREATE TABLE DummyTrans 9f@)EKBK
(DummyColumn char (8000) not null) 0(kp>%mbB
DECLARE @Counter INT, /?GBp[(0
@StartTime DATETIME, vZxy9Wmc
@TruncLog VARCHAR(255) ;CW$/^QNr5
SELECT @StartTime = GETDATE(), )Ga6O2:
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' M]'AA
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DBCC SHRINKFILE (@LogicalFileName, @NewSize) ieI-_]|[
EXEC (@TruncLog) H~@h
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-- Wrap the log if necessary. WIghP5% W
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired :Ls36E8f=
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) BpC Sf.zZ
AND (@OriginalSize * 8 /1024) > @NewSize 5J;c;PF
BEGIN -- Outer loop. u|ZO"t
SELECT @Counter = 0 3LmHH
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WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) oMPQkj;
BEGIN -- update 6i4j(P
INSERT DummyTrans VALUES ('Fill Log') V;V9_qP,
DELETE DummyTrans c1^3lgPv
SELECT @Counter = @Counter + 1 p
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END +D@R'$N
EXEC (@TruncLog) (07d0 <<[
END "duJl-
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ,Tx8^|b#F
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + K+\hv~+@
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' r$7rYxFR
FROM sysfiles ;1%a:#5
WHERE name = @LogicalFileName )&9RoW()?
DROP TABLE DummyTrans .EdV36$n
SET NOCOUNT OFF nAzr!$qbNv
8、说明:更改某个表 by<2hLB9Q
exec sp_changeobjectowner 'tablename','dbo' (tgaH,G
9、存储更改全部表 u;!Rv E8N
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch UO wNcY
@OldOwner as NVARCHAR(128), !S:@x.n@iR
@NewOwner as NVARCHAR(128) q~3&f
AS lySa Jd
DECLARE @Name as NVARCHAR(128) QZlUUj\
DECLARE @Owner as NVARCHAR(128) &<V~s/n=6?
DECLARE @OwnerName as NVARCHAR(128) pr"flRQr#
DECLARE curObject CURSOR FOR 0TpA3K
select 'Name' = name, -}J8|gwwp
'Owner' = user_name(uid) *l//r
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from sysobjects Go|65Z\`7M
where user_name(uid)=@OldOwner #5D+XB T
order by name =Vs<DO{|4q
OPEN curObject {aSq3C<r
FETCH NEXT FROM curObject INTO @Name, @Owner rXPXO=F1/
WHILE(@@FETCH_STATUS=0) {>Px.%[<
BEGIN D\R^*k@V
if @Owner=@OldOwner sn(}5;
begin N;Hv B:c
set @OwnerName = @OldOwner + '.' + rtrim(@Name) *"ShE=\p
exec sp_changeobjectowner @OwnerName, @NewOwner 0u_'(Z-^2
end +[ zo2lBx
-- select @name,@NewOwner,@OldOwner ^Ram8fW
FETCH NEXT FROM curObject INTO @Name, @Owner w(D9'
END hd~rC*I
close curObject 5IK@<#wE
deallocate curObject 2. _cEY34
GO s<b7/;w'
10、SQL SERVER中直接循环写入数据 (R-Q9F+;
declare @i int ~'3% Qr
set @i=1 ooQ( bF
while @i<30 wk#QQDV3|0
begin gISs+g
insert into test (userid) values(@i) ${wE5^ky
set @i=@i+1 e?>suIB
end R 6Em^A/>
小记存储过程中经常用到的本周,本月,本年函数 fm0(
Dateadd(wk,datediff(wk,0,getdate()),-1) RHbwq]
Dateadd(wk,datediff(wk,0,getdate()),6) bed+Ur&
Dateadd(mm,datediff(mm,0,getdate()),0) ;Y\,2b, xh
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) UZra'+Wb
Dateadd(yy,datediff(yy,0,getdate()),0) *$VurqLn
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) JyO lVs<T
上面的SQL代码只是一个时间段 BP$#a
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Dateadd(wk,datediff(wk,0,getdate()),-1) "+&<Q d2
Dateadd(wk,datediff(wk,0,getdate()),6) 4(82dmKO
就是表示本周时间段. ny= {V*m
下面的SQL的条件部分,就是查询时间段在本周范围内的: R
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Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) Mk[`HEO
而在存储过程中 27:x5g?
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) Hw{Y.@)4R
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 1tW:(~=a;