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。 _~&6Kb^*
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一、基础 $/Gvz)M
1、说明:创建数据库 BDNn~aU#m
CREATE DATABASE database-name P_B#
2、说明:删除数据库 -/ ;y*mP
drop database dbname zu5'Ex`gQa
3、说明:备份sql server T(MS,AyD]
--- 创建 备份数据的 device Sav]Kxq{
USE master M")J buI
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' @ H=
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--- 开始 备份 am{f<v,EI
BACKUP DATABASE pubs TO testBack oN)l/"%C7/
4、说明:创建新表 =SB#rCH
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) {^i7 3}@O
根据已有的表创建新表: S 3Tp__
A:create table tab_new like tab_old (使用旧表创建新表) Q g"hN
B:create table tab_new as select col1,col2... from tab_old definition only hF s:9
5、说明:删除新表 01g=Cg
drop table tabname 5DK>4H:
6、说明:增加一个列 K}tl,MMU
Alter table tabname add column col type /1F%w8Iqh
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 %I9{)'+@x
7、说明:添加主键: Alter table tabname add primary key(col) X|q&0W=
说明:删除主键: Alter table tabname drop primary key(col) #:s*)(Qn
8、说明:创建索引:create [unique] index idxname on tabname(col....) [4"1TyW
删除索引:drop index idxname [mn@/qf
注:索引是不可更改的,想更改必须删除重新建。 kQ7$,K#
9、说明:创建视图:create view viewname as select statement WjW+EF8(
删除视图:drop view viewname 0^az<!!O#
10、说明:几个简单的基本的sql语句 :'91qA%Wr
选择:select * from table1 where 范围 D*6v.`]X
插入:insert into table1(field1,field2) values(value1,value2) mcy\nAf5%
删除:delete from table1 where 范围 '$YB
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更新:update table1 set field1=value1 where 范围 +>/ariRr
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! Ve*NM|jg
排序:select * from table1 order by field1,field2 [desc] rL3<r
总数:select count as totalcount from table1 7Ab&C&3
求和:select sum(field1) as sumvalue from table1 ']Gqa$(YC
平均:select avg(field1) as avgvalue from table1 k"&loh
最大:select max(field1) as maxvalue from table1 $}_N379&
最小:select min(field1) as minvalue from table1 Oi AZA<
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11、说明:几个高级查询运算词 6!dbJ5x1
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A: UNION 运算符 rl4B(NZi}
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。 M(|Qvh{Q6
B: EXCEPT 运算符 v".q578
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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。 fft FNHP
C: INTERSECT 运算符 JQ=i{ 9iJ
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。 _x&;Fa%
注:使用运算词的几个查询结果行必须是一致的。 gD10C,{
12、说明:使用外连接 [Oen{c9A
A、left outer join: %KHO}gad1
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。 o(w!x!["
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 k4fc5P
B:right outer join: .)
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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。 B4 yU}v
C:full outer join: *GleeJWz
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。 7 4Xk^8
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二、提升 C~4_Vc*
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) JBfDz0P
法一:select * into b from a where 1<>1 mR@|] T
法二:select top 0 * into b from a vw5f.8T;w
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) Z:DEET!c'k
insert into b(a, b, c) select d,e,f from b; RO[Ko-m|/N
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) J ^gtSn^
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 HM57b>6
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. <~;; iM6
4、说明:子查询(表名1:a 表名2:b) '{dduHo
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) %E#OUo[y/
5、说明:显示文章、提交人和最后回复时间 #<0Yx9Jh.
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b ,Tc3koi
6、说明:外连接查询(表名1:a 表名2:b) 5OeTOI()&5
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ZycV?ob8}
7、说明:在线视图查询(表名1:a ) 5I/wP qR[
select * from (SELECT a,b,c FROM a) T where t.a > 1; nfpkWyI u{
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 `q|&;wP.
select * from table1 where time between time1 and time2 mAMi-9
select a,b,c, from table1 where a not between 数值1 and 数值2 VeiJ1=hc
9、说明:in 的使用方法 JLUG=x(dA
select * from table1 where a [not] in ('值1','值2','值4','值6') g?`g+:nug
10、说明:两张关联表,删除主表中已经在副表中没有的信息 t\~lGG-p
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) i)9}+M5
11、说明:四表联查问题: ;, P-2\V/
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 ..... _nu,ks+
12、说明:日程安排提前五分钟提醒 Tlrr02>B{
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 IN=pki|.
13、说明:一条sql 语句搞定数据库分页 VH[r@Pn
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 BCsz8U!
14、说明:前10条记录 MJNY#v3
select top 10 * form table1 where 范围 Vcn04j#Q
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.) f0p+l-iEv
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) QK _1!t3
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 N<lejZ}!q
(select a from tableA ) except (select a from tableB) except (select a from tableC) w1HE^
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17、说明:随机取出10条数据 =OfU#i"c
select top 10 * from tablename order by newid() -YM#.lQ
18、说明:随机选择记录 3 i<,#FaL
select newid() n,sf$9"
19、说明:删除重复记录 "hwg";Z$n
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) f!6oW( r-L
20、说明:列出数据库里所有的表名 =|>CB
select name from sysobjects where type='U' hY
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21、说明:列出表里的所有的 [-o`^;
select name from syscolumns where id=object_id('TableName') Gr9/@U+
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。 vSty.:bY\p
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 X"WKgC g$
显示结果: T=r-6eN
type vender pcs r=GF*i[3
电脑 A 1 q/y4HT,x
电脑 A 1 MuNM)pyxp
光盘 B 2 5`qt82Qm
光盘 A 2 ,XT#V\qne
手机 B 3 nk.Y#+1)
手机 C 3 GT\,
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23、说明:初始化表table1 U'^AJ2L8
TRUNCATE TABLE table1 ~\= VSwJ
24、说明:选择从10到15的记录 bwh7.lDAl
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc kN3 T/96
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三、技巧 +pYrA qmO-
1、1=1,1=2的使用,在SQL语句组合时用的较多 vZV+24YWb
"where 1=1" 是表示选择全部 "where 1=2"全部不选,
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如: D|8vS8p
if @strWhere !='' m-f"EFmP
begin A
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere _&S?uz m
end ;>^oe:@
else iku8T*&uc
begin _XT],"
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' '[#a-8-JY_
end ~3}Gu^@
我们可以直接写成 g\MHv#v*k
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere Pn@k)g
2、收缩数据库 %bI(
--重建索引 |8I #`
DBCC REINDEX 8r
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DBCC INDEXDEFRAG .DSn
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--收缩数据和日志 (IXiwu
DBCC SHRINKDB ^l1tQnj)7
DBCC SHRINKFILE =H*}{'#
3、压缩数据库 shW$V93<
dbcc shrinkdatabase(dbname) U3r[ysf
4、转移数据库给新用户以已存在用户权限 ( Lj{V}^
exec sp_change_users_login 'update_one','newname','oldname' \)'nxFKqV
go `|K,E
5、检查备份集 b?Wg|D
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 3L/qU^`
6、修复数据库 =ark?<E
ALTER DATABASE [dvbbs] SET SINGLE_USER %M8Egr2|0
GO a%*l]S0z"
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ~ILig}I
GO ;9r
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ALTER DATABASE [dvbbs] SET MULTI_USER Q(SVJ
GO 1xK'1g72
7、日志清除 xt]Z{:.
SET NOCOUNT ON SQ#6~zxl
DECLARE @LogicalFileName sysname, d
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@MaxMinutes INT, l@`D;m
@NewSize INT MWf ]U
USE tablename -- 要操作的数据库名 V~LZ%NZ8
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 &pwSd
@MaxMinutes = 10, -- Limit on time allowed to wrap log. ]2G5ng' @
@NewSize = 1 -- 你想设定的日志文件的大小(M) <%eY>E
-- Setup / initialize `B+%W
DECLARE @OriginalSize int yu"Ii-9z
SELECT @OriginalSize = size 2}j2Bhc
FROM sysfiles ={' "ATX(U
WHERE name = @LogicalFileName ~XGO^P"?
SELECT 'Original Size of ' + db_name() + ' LOG is ' + a2W}Wb+
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + h"VQFqQy
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' Tk s;,C
FROM sysfiles {9TWPB/>
WHERE name = @LogicalFileName "cjZ6^Hum
CREATE TABLE DummyTrans Mr'}IX5
(DummyColumn char (8000) not null) H e]1<tx
DECLARE @Counter INT, E/cA6*E[.<
@StartTime DATETIME, 70_T;K6
@TruncLog VARCHAR(255) CCKg,v
SELECT @StartTime = GETDATE(), G%)?jg@EA
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' >Bp%~8f
DBCC SHRINKFILE (@LogicalFileName, @NewSize) xO'I*)
EXEC (@TruncLog) ~45u
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-- Wrap the log if necessary. E#"QaI8`
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired \C.%S +u
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 1A^iUC5)
AND (@OriginalSize * 8 /1024) > @NewSize i}
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BEGIN -- Outer loop. P8NKpO\
SELECT @Counter = 0 >JT{~SRB|Y
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) U`q[5U"
BEGIN -- update FzmCS@yA
INSERT DummyTrans VALUES ('Fill Log') k*|dX.C:
DELETE DummyTrans 2rHw5Wn]~
SELECT @Counter = @Counter + 1 Wu)ATs}
END Sp)KtMV
EXEC (@TruncLog) SCeZt [
END RAKQ+Y"nl
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ANSv ZqKh
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 9[DQ[bL
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' J#*Uf>5NY
FROM sysfiles BOJh-(>I
WHERE name = @LogicalFileName ~Wu Elns
DROP TABLE DummyTrans "@B!5s0
SET NOCOUNT OFF <[C9F1]Ya
8、说明:更改某个表 "_+X#P
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exec sp_changeobjectowner 'tablename','dbo' Ku LZg
9、存储更改全部表 wo2^,Y2z+
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch R#~}ZUk2
@OldOwner as NVARCHAR(128), G B!3`
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@NewOwner as NVARCHAR(128) Gb61X6
AS &Pxt6M\d
DECLARE @Name as NVARCHAR(128) i=_leC)rl
DECLARE @Owner as NVARCHAR(128) sb4)@/Q7j
DECLARE @OwnerName as NVARCHAR(128) tYIHsm\b
DECLARE curObject CURSOR FOR #%VprcEK
select 'Name' = name, TUhp
'Owner' = user_name(uid) *pP"u::S
from sysobjects 0kgK~\^,.O
where user_name(uid)=@OldOwner YN] w_=
order by name }7hpx!s,
OPEN curObject j5z, l
FETCH NEXT FROM curObject INTO @Name, @Owner *F:]mgg
WHILE(@@FETCH_STATUS=0) 'R_U,9y`
BEGIN D,xWc|V
if @Owner=@OldOwner qt]QO1pAd
begin v,vTRrpK
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 0!=e1_
exec sp_changeobjectowner @OwnerName, @NewOwner 3sGrX"0D
end f[7'kv5S
-- select @name,@NewOwner,@OldOwner t^?8Di\
FETCH NEXT FROM curObject INTO @Name, @Owner E E?v~6"&
END QOuy(GY
close curObject bI[!y#_z4
deallocate curObject N-^\X3X
GO /iif@5lw{
10、SQL SERVER中直接循环写入数据 +Smv<^bW
declare @i int |}Mkn4
set @i=1 sxL;o>{
while @i<30 ]wne2 WXE
begin mXc/sh")X
insert into test (userid) values(@i) *B}vYX
set @i=@i+1 :'y
end |UnTd$m
小记存储过程中经常用到的本周,本月,本年函数 ?f']*pD8
Dateadd(wk,datediff(wk,0,getdate()),-1) \!ESmxSa;
Dateadd(wk,datediff(wk,0,getdate()),6) y NV$IN%
Dateadd(mm,datediff(mm,0,getdate()),0) ?Z4&j'z<
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) };9dd3X
Dateadd(yy,datediff(yy,0,getdate()),0) =@pm-rI|-
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) xHsH .f_{
上面的SQL代码只是一个时间段 `^AbFV
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Dateadd(wk,datediff(wk,0,getdate()),-1) `H$s-PX
Dateadd(wk,datediff(wk,0,getdate()),6) |+6Z+-.Hg
就是表示本周时间段. };o R x)
下面的SQL的条件部分,就是查询时间段在本周范围内的: zQ{ Q>"-
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) t{~"vD9Am
而在存储过程中 5YS`v#+
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) vlIdi@V
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) ^'EEry