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。 VV{>Kq+&,v
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一、基础 egvb#:zW?
1、说明:创建数据库 ua)jGif
CREATE DATABASE database-name m"T}em#
2、说明:删除数据库 !E_Zh*lgm
drop database dbname q)mG6Su
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3、说明:备份sql server Z\$M)e8n
--- 创建 备份数据的 device -V4%f{9T3
USE master $~S~pvT
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ~nTj't2R
--- 开始 备份 N+ak{3
BACKUP DATABASE pubs TO testBack 8qqN0"{,
4、说明:创建新表 X Z . T%g
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) _6Y+E"@zs
根据已有的表创建新表: lXg5UrW
A:create table tab_new like tab_old (使用旧表创建新表) tYXE$i
B:create table tab_new as select col1,col2... from tab_old definition only xbBqR_H_
5、说明:删除新表 cGiL9|k
drop table tabname *f3S tX
6、说明:增加一个列 :\vs kk),
Alter table tabname add column col type |{&M#qXe
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。 )S
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7、说明:添加主键: Alter table tabname add primary key(col) +SR{FF
说明:删除主键: Alter table tabname drop primary key(col) S3:AitGJ
8、说明:创建索引:create [unique] index idxname on tabname(col....) zs~Tu
删除索引:drop index idxname Kv(R|d6Lp
注:索引是不可更改的,想更改必须删除重新建。
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9、说明:创建视图:create view viewname as select statement ~ ;LzTL
删除视图:drop view viewname 'f!U[Qatg
10、说明:几个简单的基本的sql语句 NJ)Dw`|%|)
选择:select * from table1 where 范围 ~ney~Pz_
插入:insert into table1(field1,field2) values(value1,value2) x ZP*%yM
删除:delete from table1 where 范围 +Q[uq!<VJk
更新:update table1 set field1=value1 where 范围 L;*
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查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! #R{>@]x`
排序:select * from table1 order by field1,field2 [desc] 3*&
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总数:select count as totalcount from table1 0:`|T jf_
求和:select sum(field1) as sumvalue from table1 KW(a@X
平均:select avg(field1) as avgvalue from table1 ~N/r;omVc
最大:select max(field1) as maxvalue from table1 mUbm3JIjJ
最小:select min(field1) as minvalue from table1 X%+lgm+
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11、说明:几个高级查询运算词 HT6 [Z1
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A: UNION 运算符 {g!7K
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。 :oXSh;\
B: EXCEPT 运算符 4/Y?e UQ
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。 N(Ru/9!y"
C: INTERSECT 运算符 ejlns
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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。 +U2lwd!j
注:使用运算词的几个查询结果行必须是一致的。 1!KROes4
12、说明:使用外连接 ~PI2G9
A、left outer join: E?G'F3i
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。 J7* o%W*V
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 X58U>4a
B:right outer join: bDM },(
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。 R>*z8n
C:full outer join: a(|6)w-
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。 %(1OjfZc
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二、提升 I@MG?ZQ
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) uhh7Ft#H
法一:select * into b from a where 1<>1 *qwN9b/!
法二:select top 0 * into b from a Qz,2PO
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) c1"wS*u
insert into b(a, b, c) select d,e,f from b; &h0LWPl
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) wX0D^)NtF
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 kU[hB1D5
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. F#gA2VCm
4、说明:子查询(表名1:a 表名2:b) ^o{{kju
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) /@F'f@;
5、说明:显示文章、提交人和最后回复时间
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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 <NMJkl-r8r
6、说明:外连接查询(表名1:a 表名2:b) v-tI`Qpb
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c H-PVV&r
7、说明:在线视图查询(表名1:a ) .;]WcC<3
select * from (SELECT a,b,c FROM a) T where t.a > 1; pL"{Uqi
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 x
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select * from table1 where time between time1 and time2 TKR#YJQ?K
select a,b,c, from table1 where a not between 数值1 and 数值2 oFj_o
9、说明:in 的使用方法 ^e8xg=8(
select * from table1 where a [not] in ('值1','值2','值4','值6') {^z73Gxt,
10、说明:两张关联表,删除主表中已经在副表中没有的信息 8YFG*HSa
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) taE
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11、说明:四表联查问题: r8s>s6vm
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 ..... fAgeF$9@
12、说明:日程安排提前五分钟提醒 rO7_K>g?
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 u%~'+=
13、说明:一条sql 语句搞定数据库分页 rx2)uUbR
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 y:RW:D&
14、说明:前10条记录 F
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select top 10 * form table1 where 范围 'F d+1
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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.) `eMZhYo
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) gz~oQ
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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 d}\]!x3t
(select a from tableA ) except (select a from tableB) except (select a from tableC) rLsY_7!
17、说明:随机取出10条数据 A|\A|8=b
select top 10 * from tablename order by newid() ,`}yJ*7
18、说明:随机选择记录 pUHgjwT'U
select newid() "E\vdhk
19、说明:删除重复记录 ,VS\ mG/}s
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) %JM$]
20、说明:列出数据库里所有的表名 zMv`<m%
select name from sysobjects where type='U' 0vqVE]C
21、说明:列出表里的所有的 J\y^T3Z
select name from syscolumns where id=object_id('TableName') mD'nF1o
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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。 O>' }q/
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 1
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显示结果: &<N8d(
type vender pcs 9^XZ|`
电脑 A 1 ^I!Z)/
电脑 A 1 :}e<
光盘 B 2 O2Qmz=%
光盘 A 2 MJ JC6:
手机 B 3 SaXt"Ju,AH
手机 C 3 EHwb?{
23、说明:初始化表table1 gD9CA*
TRUNCATE TABLE table1 -TF},V~
24、说明:选择从10到15的记录 N;3!oo4
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc sfX~X/
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三、技巧 :qdyCsn2
1、1=1,1=2的使用,在SQL语句组合时用的较多 VW*%q0i-
"where 1=1" 是表示选择全部 "where 1=2"全部不选, U4"^NLAq
如: |8'}mjs.Q
if @strWhere !='' L<!h3n
begin ?{ )'O+s
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ;0dH@b
end @rYZ0`E9
else +j 9+~
begin LO_Xrj
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' uVqc:Q"
end jlBsm'M<m
我们可以直接写成 h>`[p,o
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere H1k)ya x4_
2、收缩数据库 RnkV)ed(
--重建索引 zIF1A*UH
DBCC REINDEX hl:Ba2_E
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DBCC INDEXDEFRAG 4mDHAR%D
--收缩数据和日志 !V.]mI
DBCC SHRINKDB ~ EBaVl ({
DBCC SHRINKFILE 2H`r:x<Z-
3、压缩数据库 ec!e
dbcc shrinkdatabase(dbname) PB^rniYh
4、转移数据库给新用户以已存在用户权限 w5i*pOG)Z
exec sp_change_users_login 'update_one','newname','oldname' #`_W?-%^
go K6->{!8]k
5、检查备份集 ] V/5<O1
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 8XH;<z<oJ
6、修复数据库 =8l' [
ALTER DATABASE [dvbbs] SET SINGLE_USER k M/:n
GO 0kUhz\"R:q
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK wrkw,H
GO P'Y(f!%
ALTER DATABASE [dvbbs] SET MULTI_USER &MX&5@
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GO l -XfUjJ
7、日志清除 1|p\rHGd
SET NOCOUNT ON <sC(a7i1
DECLARE @LogicalFileName sysname, fQ 9af)d
@MaxMinutes INT, NuO@Nr
@NewSize INT DNmC
USE tablename -- 要操作的数据库名 oc"p5Y3,Os
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 Zna6-0o
@MaxMinutes = 10, -- Limit on time allowed to wrap log. ~;HASHu
@NewSize = 1 -- 你想设定的日志文件的大小(M) ?*~
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-- Setup / initialize [\ku,yd%0
DECLARE @OriginalSize int \;-Yz
SELECT @OriginalSize = size @{IX
do
FROM sysfiles <2(X?,N5BD
WHERE name = @LogicalFileName UT@Qo}:
SELECT 'Original Size of ' + db_name() + ' LOG is ' + tXzuP_0
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + <IZr..|O
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' S_sHwObFu|
FROM sysfiles
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WHERE name = @LogicalFileName q}_8iDO6
CREATE TABLE DummyTrans OkRb3}
(DummyColumn char (8000) not null) \ ERBb.
DECLARE @Counter INT, <\~@l^lU
@StartTime DATETIME, A@3'I ;
@TruncLog VARCHAR(255) 'cCM[P+
SELECT @StartTime = GETDATE(), ar@,SKU'K
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' Z84w9y7O<
DBCC SHRINKFILE (@LogicalFileName, @NewSize) d*TH$-F!p
EXEC (@TruncLog) yHY2 SXm
-- Wrap the log if necessary. w%wVB/(
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired [ (Y@
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) @w33u^
AND (@OriginalSize * 8 /1024) > @NewSize JXuks`:Q
BEGIN -- Outer loop. p!E*ANwX
SELECT @Counter = 0 AIP0PJI3
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) g#P]72TQ
BEGIN -- update |+h x2?Nv
INSERT DummyTrans VALUES ('Fill Log') k6 OO\=
DELETE DummyTrans -wUT@a
SELECT @Counter = @Counter + 1 =n.&N
END <YCjo[(~
EXEC (@TruncLog) GB+$ed5@<
END 7IUJHc[R?
SELECT 'Final Size of ' + db_name() + ' LOG is ' + vmxS^_I
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ^E,
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CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ]Y,V)41gCE
FROM sysfiles 1^AQLOiRE1
WHERE name = @LogicalFileName yu#m6K
DROP TABLE DummyTrans `_D A!
SET NOCOUNT OFF \HD:#a
8、说明:更改某个表 6oWFj eZ0
exec sp_changeobjectowner 'tablename','dbo' |s#,^SJ0
9、存储更改全部表 cm!vuoB~~
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch iJZvVs',
@OldOwner as NVARCHAR(128), :"Vmy.xq
@NewOwner as NVARCHAR(128) L]YJ#5
AS E\2f"s
DECLARE @Name as NVARCHAR(128) e<DcuF<ZS
DECLARE @Owner as NVARCHAR(128) kJ* N`=
DECLARE @OwnerName as NVARCHAR(128) An]Vx<PD
DECLARE curObject CURSOR FOR -Nr*na^H9#
select 'Name' = name, <}^p5|
'Owner' = user_name(uid) )1R[~]y
from sysobjects MHE/#G
where user_name(uid)=@OldOwner P/S ,dhs(
order by name de8xl
OPEN curObject shLMj)7!
FETCH NEXT FROM curObject INTO @Name, @Owner >d;U>P5.
WHILE(@@FETCH_STATUS=0) f!7fz~&Sh
BEGIN ,jnaa (n
if @Owner=@OldOwner JrxQ.,*i
begin :MYLap&L&
set @OwnerName = @OldOwner + '.' + rtrim(@Name) [$6YPM>Ee
exec sp_changeobjectowner @OwnerName, @NewOwner ;Gp9
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end U4"&T,'lTL
-- select @name,@NewOwner,@OldOwner )REegFN@
FETCH NEXT FROM curObject INTO @Name, @Owner /`qQWB5b
END ;Gu(Yoa}y
close curObject }V/iU_)
deallocate curObject ~Y1nU-
GO 6d5q<C_3t
10、SQL SERVER中直接循环写入数据 iOAn/[^xk
declare @i int 3? k<e
set @i=1 C,O9?t
while @i<30 1Uah IePf
begin ZRGe$HaU
insert into test (userid) values(@i) jJ
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set @i=@i+1 B&(/,.
end ?J|
小记存储过程中经常用到的本周,本月,本年函数 _Kli~$c& M
Dateadd(wk,datediff(wk,0,getdate()),-1) D=f$-rn
Dateadd(wk,datediff(wk,0,getdate()),6) Y|#<kS
Dateadd(mm,datediff(mm,0,getdate()),0) Zirp_[KZ%
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 6!6R3Za$
Dateadd(yy,datediff(yy,0,getdate()),0) 29z@ !
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) XB[EJGaX
上面的SQL代码只是一个时间段 B$q5/ L$}
Dateadd(wk,datediff(wk,0,getdate()),-1) 1n)YCSA
Dateadd(wk,datediff(wk,0,getdate()),6) .5~3D97X&
就是表示本周时间段. -Zg.o$
下面的SQL的条件部分,就是查询时间段在本周范围内的: Q*f0YjH!
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) Rto/-I0l
而在存储过程中 xgsEe3|
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ZlMS=<hgFx
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 6m:$RW