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。 ;tG@ 6
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一、基础 nz_1Fu>g|
1、说明:创建数据库 ,f)#&}x*2+
CREATE DATABASE database-name 0jmPj
2、说明:删除数据库 Ro:)N:C
drop database dbname vH)V\V
3、说明:备份sql server `Ti?hQm/
--- 创建 备份数据的 device ujan2'YT
USE master =QJI_veUG`
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 6!$2nK+
--- 开始 备份 >NMq^J'/
BACKUP DATABASE pubs TO testBack -W'T3_
4、说明:创建新表 cZl/8?dj}
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) AoFxh o
根据已有的表创建新表: U])$#/ v
A:create table tab_new like tab_old (使用旧表创建新表) `w
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B:create table tab_new as select col1,col2... from tab_old definition only s~n@|m9k
5、说明:删除新表 kH" >(f
drop table tabname >}) W5Y+
6、说明:增加一个列 pWOK~=t
Alter table tabname add column col type ;:Q&Rf"@%
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。 =niT]xf
7、说明:添加主键: Alter table tabname add primary key(col) mT&?DZ9<
说明:删除主键: Alter table tabname drop primary key(col) 5"mH6%d :8
8、说明:创建索引:create [unique] index idxname on tabname(col....) Un^3%=;
删除索引:drop index idxname /M5R<rl
注:索引是不可更改的,想更改必须删除重新建。 C|-QU
9、说明:创建视图:create view viewname as select statement ^j *H
删除视图:drop view viewname xjH({(/B>a
10、说明:几个简单的基本的sql语句 H-/w8_} KG
选择:select * from table1 where 范围 b<\aJb{2
插入:insert into table1(field1,field2) values(value1,value2) +(/' b'*
删除:delete from table1 where 范围 N"-U)d-.
更新:update table1 set field1=value1 where 范围 j:P(,M[
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! @G?R(
排序:select * from table1 order by field1,field2 [desc] DTo P|P
总数:select count as totalcount from table1 2 i97
求和:select sum(field1) as sumvalue from table1 <}('w/
平均:select avg(field1) as avgvalue from table1 b/6!>qMMk%
最大:select max(field1) as maxvalue from table1 #iVr @|,
最小:select min(field1) as minvalue from table1 vTq
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11、说明:几个高级查询运算词 6)[gF1
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A: UNION 运算符 ?4H>1Wkb
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。 JN> h:
B: EXCEPT 运算符 h)pYV>!d
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。 qt`HP3J&
C: INTERSECT 运算符 !~fy".|x
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。 6YF<GF{
注:使用运算词的几个查询结果行必须是一致的。 F42?h:y8I
12、说明:使用外连接 QQ\\:]iM
A、left outer join: k<QZ_*x}G
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。 V|j{#;
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 .M( [n-
B:right outer join: *_H^]wNJG
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。 v%E~sX&CG
C:full outer join: ykD-L^}
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。 4`'V%)M
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二、提升 X1FKcWv
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) wuKr9W9Xa
法一:select * into b from a where 1<>1 > K s.
法二:select top 0 * into b from a tNC;CP#R+
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ^7iP!-w/
insert into b(a, b, c) select d,e,f from b; ^Fg!.X_
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) oz&RNB.K
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件
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例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. OCv,EZ
4、说明:子查询(表名1:a 表名2:b) /amWf^z
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) V#TNv0&0
5、说明:显示文章、提交人和最后回复时间 ra}t#Xt`
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b Q=h37]U+
6、说明:外连接查询(表名1:a 表名2:b) Rgb&EnVW
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 1a_;(T
7、说明:在线视图查询(表名1:a ) S0H|:J
select * from (SELECT a,b,c FROM a) T where t.a > 1; \e' oAhM
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 8/zv3.+[
select * from table1 where time between time1 and time2 Uc( z|
select a,b,c, from table1 where a not between 数值1 and 数值2 X6so)1jJ
9、说明:in 的使用方法 r:--DKt
select * from table1 where a [not] in ('值1','值2','值4','值6') Q9{f'B
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ZDbzH=[
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) rj/1AK
11、说明:四表联查问题: Z=9gok\
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 ..... &}!AjA)
12、说明:日程安排提前五分钟提醒 SlI
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SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 uxbLoE
13、说明:一条sql 语句搞定数据库分页 DA^!aJ6iF
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 :Ny^-4-N
14、说明:前10条记录 f6`W(OiE
select top 10 * form table1 where 范围 m;{(U Z
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.) oq[r+E-]$@
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) C=8IQl[^e
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 `*y%[J,I#
(select a from tableA ) except (select a from tableB) except (select a from tableC) 3v>w$6
17、说明:随机取出10条数据 *X8Pa;x
select top 10 * from tablename order by newid() EL(BXJrx{
18、说明:随机选择记录 .\mkgAlyaM
select newid() o,[Em<
19、说明:删除重复记录 ~mC>G 4y$a
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) IubzHf
20、说明:列出数据库里所有的表名 z
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select name from sysobjects where type='U' ? $.x%G+
21、说明:列出表里的所有的 g4&f2D5
select name from syscolumns where id=object_id('TableName') FXh*!%"*
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。 8f>v[SQ"
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 iM M s3
显示结果: ?\_vqW
type vender pcs ?D['>Rzu
电脑 A 1 @nOuFX4
电脑 A 1 zuI7Px
光盘 B 2
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光盘 A 2 lu;gmWz
手机 B 3 *3rp
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手机 C 3 )0zg1z
23、说明:初始化表table1 gf70 O>E
TRUNCATE TABLE table1 )WsR
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24、说明:选择从10到15的记录 z-^/<u1p
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ta0 ;:o?/d
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三、技巧 :
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1、1=1,1=2的使用,在SQL语句组合时用的较多 GjyTM
"where 1=1" 是表示选择全部 "where 1=2"全部不选, z[l_<`J$9
如: ]T._TZ"
if @strWhere !='' V\=%u<f
begin py$i{v%
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere {Zo*FZcaX
end 4@=[rZb9
else
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begin MUUhg
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' EpK7VW
end m O"Rq5
我们可以直接写成 sNZOm $
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere R0e!b+MZ.
2、收缩数据库 C:z7R" yj
--重建索引 .p%V]Ka
DBCC REINDEX O)c3Lm-w
DBCC INDEXDEFRAG X0 ]Se(
--收缩数据和日志 WF-^pfRq~
DBCC SHRINKDB I].ddR%
DBCC SHRINKFILE (5kL6d2
3、压缩数据库 &/?OP)N,}
dbcc shrinkdatabase(dbname) kW&zkE{
4、转移数据库给新用户以已存在用户权限 2XyC;RWJ%
exec sp_change_users_login 'update_one','newname','oldname' {7.uwIW.1
go !eP0b~$/^J
5、检查备份集 HpS1(%d"
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' DTl&V|h$
6、修复数据库 BirnCfj/2
ALTER DATABASE [dvbbs] SET SINGLE_USER ik5"9b-\<
GO I5E+=.T*ar
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK x\pygzQ/
GO :=\`P
ALTER DATABASE [dvbbs] SET MULTI_USER d?><+!a
GO '![VA8
7、日志清除 G0(A~Q"
SET NOCOUNT ON e}ivvs2
DECLARE @LogicalFileName sysname, uTrQ<|}#
@MaxMinutes INT, H[N~)3x
@NewSize INT cFHSMRB|P
USE tablename -- 要操作的数据库名 :3D[~-/S
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 cd] X5)$h
@MaxMinutes = 10, -- Limit on time allowed to wrap log. dTqL[?wH?
@NewSize = 1 -- 你想设定的日志文件的大小(M) xP &@|Ag
-- Setup / initialize O^IS:\JX&
DECLARE @OriginalSize int 3
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SELECT @OriginalSize = size -Fc 9mv(H
FROM sysfiles
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WHERE name = @LogicalFileName wrVR[v>E<
SELECT 'Original Size of ' + db_name() + ' LOG is ' + syk,e4:oA
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + NN~PWy1opa
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' $'KhA6u
FROM sysfiles ~R7{gCqdr
WHERE name = @LogicalFileName GK&R.R]
CREATE TABLE DummyTrans CJ [e^K{
(DummyColumn char (8000) not null) qWJap-hb
DECLARE @Counter INT, {'cdi`
@StartTime DATETIME, Vk%W4P"l
@TruncLog VARCHAR(255) j#${L6
SELECT @StartTime = GETDATE(), &Qt1~#1
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' Tj=@5lj0
DBCC SHRINKFILE (@LogicalFileName, @NewSize) PMe 3Or@
EXEC (@TruncLog) @'"7[k!y;
-- Wrap the log if necessary. lr$,=P`
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired )6
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AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) Hnf?`j>
AND (@OriginalSize * 8 /1024) > @NewSize Z|j\_VKhl
BEGIN -- Outer loop. y2Vc[o(NP
SELECT @Counter = 0 yppXecFJ
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) c[EG
cY={
BEGIN -- update h8P_/.+g|V
INSERT DummyTrans VALUES ('Fill Log') 4g?qKoc
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DELETE DummyTrans 8xHjdQr
SELECT @Counter = @Counter + 1 }R`}Ey|{
END LP) IL~
EXEC (@TruncLog) QY$4D;M`g6
END ^?T,>ZI
SELECT 'Final Size of ' + db_name() + ' LOG is ' + sNJ?Z"5k1h
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + PcvA/W
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' F2v9XMi
FROM sysfiles \ $
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WHERE name = @LogicalFileName .&/A!3pW
DROP TABLE DummyTrans f0g&=k{OD
SET NOCOUNT OFF \8`^QgV`@
8、说明:更改某个表 EI@ep~
exec sp_changeobjectowner 'tablename','dbo' kv`5"pa7M
9、存储更改全部表 $B`bsJ
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch )T@+"Pw8t
@OldOwner as NVARCHAR(128), \p\rPfY{>
@NewOwner as NVARCHAR(128) g$mqAz<
AS %Gm4,+8P3o
DECLARE @Name as NVARCHAR(128) WiFZY*iu5
DECLARE @Owner as NVARCHAR(128) h|ja67VG
DECLARE @OwnerName as NVARCHAR(128) @@|H8mP}H
DECLARE curObject CURSOR FOR kaV Ye)~
select 'Name' = name, %Z(lTvqG
'Owner' = user_name(uid) ]v.Yt/&C{
from sysobjects /!-ypIY
where user_name(uid)=@OldOwner ;o.,vQF*
order by name "H}ae7@
OPEN curObject QM'>)!8
FETCH NEXT FROM curObject INTO @Name, @Owner 2_){4+,fu
WHILE(@@FETCH_STATUS=0) EZ^M?awB4
BEGIN 4'XCO+i#
if @Owner=@OldOwner h3;RVtS
begin Wl3fR[@3Q
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ; T WYO
exec sp_changeobjectowner @OwnerName, @NewOwner 1JN/oq;
end k)JwCt.%
-- select @name,@NewOwner,@OldOwner #K/#-S
FETCH NEXT FROM curObject INTO @Name, @Owner Y'o.`':\~
END zxvowM
close curObject (rSBzM]H
deallocate curObject 6d YUMqQ
GO =Lr#
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10、SQL SERVER中直接循环写入数据 >{juw&Uu
declare @i int r'u[>uY
set @i=1 8C2!Wwz`J8
while @i<30 VB{G%!}
begin 5va ;Ol4
insert into test (userid) values(@i) =eG:Scoug?
set @i=@i+1 m`/!7wQs
end [
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小记存储过程中经常用到的本周,本月,本年函数 U&y?3
Dateadd(wk,datediff(wk,0,getdate()),-1) sB`zk[R;
Dateadd(wk,datediff(wk,0,getdate()),6) fhe%5#3
Dateadd(mm,datediff(mm,0,getdate()),0) YR$d\,#R
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ">S.~'ds
Dateadd(yy,datediff(yy,0,getdate()),0) If(IG]>`D
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) +#ANc;2g
上面的SQL代码只是一个时间段 ;,:w%.
Dateadd(wk,datediff(wk,0,getdate()),-1) LzkwgcR
Dateadd(wk,datediff(wk,0,getdate()),6) j~Ubpf
就是表示本周时间段. Mhg_z.Z
下面的SQL的条件部分,就是查询时间段在本周范围内的: r$-]NYPi
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) vm "dE4W=
而在存储过程中 :@+@vM;gh
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) gnU##Km|
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) +4k7ti1Qb