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。 8U}+9
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一、基础 D
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1、说明:创建数据库 _9q byhS7
CREATE DATABASE database-name uh%
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2、说明:删除数据库 fYpJ2y-sA
drop database dbname {ft |*
3、说明:备份sql server | GN/{KH]
--- 创建 备份数据的 device 'p@m`)Z
USE master )0g!lCfb
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' `gyke2n
--- 开始 备份 /F6"uZSt4
BACKUP DATABASE pubs TO testBack 'H#0-V"=
4、说明:创建新表 R<O Rw]
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) FR>[g`1
根据已有的表创建新表: /U-+ClZi@
A:create table tab_new like tab_old (使用旧表创建新表) Cq'{%
B:create table tab_new as select col1,col2... from tab_old definition only HTMg{_r(%
5、说明:删除新表 W8r"dK
drop table tabname bZ^'_OOn
6、说明:增加一个列 Rt5pl,Nf
Alter table tabname add column col type v6Wz:|G/u
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。 'K01"`#
7、说明:添加主键: Alter table tabname add primary key(col) Z#D*HAd`
说明:删除主键: Alter table tabname drop primary key(col) (:\L@j
8、说明:创建索引:create [unique] index idxname on tabname(col....) J#jFX
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删除索引:drop index idxname B I=57
注:索引是不可更改的,想更改必须删除重新建。 JSmg6l?[u
9、说明:创建视图:create view viewname as select statement Ql9>i;AGV
删除视图:drop view viewname 1_l)$"
10、说明:几个简单的基本的sql语句 pF9WKpzE
选择:select * from table1 where 范围 6/ T/A+u
插入:insert into table1(field1,field2) values(value1,value2) P&<NcOCL&
删除:delete from table1 where 范围 Onou:kmf1
更新:update table1 set field1=value1 where 范围 Q2:rWE{K!
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! %oquHkX%OJ
排序:select * from table1 order by field1,field2 [desc] %UhLCyC/
总数:select count as totalcount from table1 *{5/" H5
求和:select sum(field1) as sumvalue from table1 ;=k{[g 'gv
平均:select avg(field1) as avgvalue from table1 -yb7s2o
最大:select max(field1) as maxvalue from table1 kD7'BP/#
最小:select min(field1) as minvalue from table1 )rlkQ'DN
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11、说明:几个高级查询运算词 lY2~{Y|4s
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A: UNION 运算符 R&g&BF
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 h7@%}<%
B: EXCEPT 运算符 RGkV%u^
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 f.bw A x
C: INTERSECT 运算符 }RKsS3}
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。
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注:使用运算词的几个查询结果行必须是一致的。 =#[t!-@
12、说明:使用外连接 OW@"j;6
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A、left outer join: :$gs7<z{rm
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。 atw*t1)g
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 jeJspch+#
B:right outer join: c;!|=
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。 _8-T?j**
C:full outer join: /3VO!V]u
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。 PgHmOs
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二、提升 Bjj=UtI
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) f8V
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法一:select * into b from a where 1<>1 2J%L%6z8~
法二:select top 0 * into b from a IXlk1tHN4I
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) BE],PCpPr
insert into b(a, b, c) select d,e,f from b; 0c1=M|2
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) 8~~ k?
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 (I(U23A~
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. /m,i,NX07
4、说明:子查询(表名1:a 表名2:b) b\zq,0%
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) 2(Yg',aMY-
5、说明:显示文章、提交人和最后回复时间 )?$@cvf
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b +nim47
6、说明:外连接查询(表名1:a 表名2:b) *5?Qam3
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c b?VByJl
7、说明:在线视图查询(表名1:a ) -AU'1iRcK7
select * from (SELECT a,b,c FROM a) T where t.a > 1; Gpcordt/
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 jTZi<
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select * from table1 where time between time1 and time2 @<X[,Mj
select a,b,c, from table1 where a not between 数值1 and 数值2 ,fN <I
9、说明:in 的使用方法 ZNpC&
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select * from table1 where a [not] in ('值1','值2','值4','值6') _qpIdQBo
10、说明:两张关联表,删除主表中已经在副表中没有的信息 !q$>6P
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) fe"w--v
11、说明:四表联查问题: >Z<ZT
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 ..... qs= i+
12、说明:日程安排提前五分钟提醒 gg8)oc+w
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 y 4aT-^C'
13、说明:一条sql 语句搞定数据库分页 %e)vl[:}
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 ~l.C-
14、说明:前10条记录 +JY8"a97>
select top 10 * form table1 where 范围 UV av^<_
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.) Y C<FKWc
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) w5rtYTI
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 6c27X/'Z
(select a from tableA ) except (select a from tableB) except (select a from tableC) ="f-I9y
17、说明:随机取出10条数据 Io>U-Zd\>
select top 10 * from tablename order by newid() I9rQX9#B
18、说明:随机选择记录 O8N1gf;t
select newid() ~E_irzOFP
19、说明:删除重复记录 c* ~0R?
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) *~cNUyd
20、说明:列出数据库里所有的表名 Ux{QYjFE
select name from sysobjects where type='U' ~X %cbFom=
21、说明:列出表里的所有的 2']0c
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select name from syscolumns where id=object_id('TableName') m^0 I3;
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。 C8YStT
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 t6kLZ
显示结果: TDy)A2Z
type vender pcs )56L`5#tS
电脑 A 1 gp~-n7'~O
电脑 A 1 ;~WoJlEK3
光盘 B 2 5p:2gsk
光盘 A 2 -]Mk}
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手机 B 3 GukwN]*OY
手机 C 3 VkJTcC:1
23、说明:初始化表table1 X7:Dw]t
TRUNCATE TABLE table1 dS \n2Qb
24、说明:选择从10到15的记录 3-n&&<
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc \$t{K
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三、技巧 b
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1、1=1,1=2的使用,在SQL语句组合时用的较多 NNTrH\SU#
"where 1=1" 是表示选择全部 "where 1=2"全部不选, t\!5$P
如: 0"+QWh
if @strWhere !='' QJ>=a./
begin cIkA ~F
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere UYQ@ub
end /X#OX8gb]
else I\rjw$V#
begin 9ao?\]&t
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' f(K1,L:&7
end ;ByCtVm2
我们可以直接写成 #q9BU:
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere |Xd&aQ
2、收缩数据库 sk0/3X*Q%
--重建索引 vp d!|/
DBCC REINDEX gu'+kw
DBCC INDEXDEFRAG 7)Tix7:9S;
--收缩数据和日志 |8x_Av0
DBCC SHRINKDB i12G\Ye
DBCC SHRINKFILE j.+,c#hFo
3、压缩数据库 Et}%sdS
dbcc shrinkdatabase(dbname) #.Ly
4、转移数据库给新用户以已存在用户权限 4"{g{8
exec sp_change_users_login 'update_one','newname','oldname' //Xz
go 20` XklV
5、检查备份集 L ]BTX]
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 73tjDO7d
6、修复数据库 d)XT> &
ALTER DATABASE [dvbbs] SET SINGLE_USER r8FAV9A
GO ^<v.=7cL0
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK
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GO A,=
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ALTER DATABASE [dvbbs] SET MULTI_USER FgPmQ
GO zx"0^r}
7、日志清除 |BGzdBm^x:
SET NOCOUNT ON Yx ;j
DECLARE @LogicalFileName sysname, to#2.
@MaxMinutes INT, F0r5$Pl*
@NewSize INT 09G]t1!,
USE tablename -- 要操作的数据库名
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SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 xcJvXp
@MaxMinutes = 10, -- Limit on time allowed to wrap log. f)Z'#[A*t7
@NewSize = 1 -- 你想设定的日志文件的大小(M) X\<a|/{V A
-- Setup / initialize Y!|};
DECLARE @OriginalSize int (.{. "
SELECT @OriginalSize = size m5KLi
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FROM sysfiles QEx&AT
WHERE name = @LogicalFileName mcQ\"9 ;pY
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 6jl{^dI
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + pMp@W`i^6
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' Tm~jYgJ
FROM sysfiles *t={9h
WHERE name = @LogicalFileName >Wpd q( o
CREATE TABLE DummyTrans =aehhs>
(DummyColumn char (8000) not null) O&">%aU1I
DECLARE @Counter INT, v57Kr ,
@StartTime DATETIME, do%.KIk
@TruncLog VARCHAR(255) MUN:}S
SELECT @StartTime = GETDATE(), =3,Sjme
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' nXxnyom,
DBCC SHRINKFILE (@LogicalFileName, @NewSize) )%!X,
EXEC (@TruncLog) y G>sBc
-- Wrap the log if necessary. R/^;,.
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired o9v9
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AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ~i}/
AND (@OriginalSize * 8 /1024) > @NewSize =)]RD%Oq
BEGIN -- Outer loop. 91#n Aj%
SELECT @Counter = 0 %]O#t<D
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ]7h;MR
BEGIN -- update xz,M>Ua
INSERT DummyTrans VALUES ('Fill Log') dsbz\w3:
DELETE DummyTrans ;:Kc{B.s
SELECT @Counter = @Counter + 1 \nQEvcH
END i{J[;rV9
EXEC (@TruncLog) >>=v`}
END z_z'3d.r7
SELECT 'Final Size of ' + db_name() + ' LOG is ' + a1weTn*
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + RZj06|r8
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' <)@^TRS
FROM sysfiles Pp|pH|(n ,
WHERE name = @LogicalFileName fK=vLcH
DROP TABLE DummyTrans $>%zNq-F
SET NOCOUNT OFF w Kz*)C
8、说明:更改某个表 8[8U49V9(
exec sp_changeobjectowner 'tablename','dbo' jqoU;u`
9、存储更改全部表 ['0^gN$:e
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch
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@OldOwner as NVARCHAR(128), +Pn`AV1
@NewOwner as NVARCHAR(128) Zo,]Dx
AS a+\s 0Qo<
DECLARE @Name as NVARCHAR(128) HMR!XF&JjC
DECLARE @Owner as NVARCHAR(128) 8ZO~=e
DECLARE @OwnerName as NVARCHAR(128) Gv\fF;,R
DECLARE curObject CURSOR FOR nON"+c*
select 'Name' = name, lt}U,p,S
'Owner' = user_name(uid) ra\|c>[%
from sysobjects I,lzyxRP
where user_name(uid)=@OldOwner An
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order by name NW Pd~l+
OPEN curObject .GPuKP|
FETCH NEXT FROM curObject INTO @Name, @Owner @(rLn
WHILE(@@FETCH_STATUS=0) rX&?Xi1JeV
BEGIN `P9%[8`C 9
if @Owner=@OldOwner sY'dN_F
begin 'zTa]y]a
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 6IM:Xj
exec sp_changeobjectowner @OwnerName, @NewOwner P99s
end m3_)UIJZ
-- select @name,@NewOwner,@OldOwner #DHeEE
FETCH NEXT FROM curObject INTO @Name, @Owner niM(0p
END );x[1*e
close curObject :SpPT
deallocate curObject !myF_cv}'
GO >Q^*h}IdW
10、SQL SERVER中直接循环写入数据 \Ng[lN
declare @i int qk(u5Z
set @i=1 * (<3 oIRS
while @i<30 dtq]_HvTJ
begin yAVt[+0
insert into test (userid) values(@i) vy F(k3W
set @i=@i+1 UIw6~a3E
end eYRm:KC
小记存储过程中经常用到的本周,本月,本年函数 YA^g[,
Dateadd(wk,datediff(wk,0,getdate()),-1) Z?'){\$*
Dateadd(wk,datediff(wk,0,getdate()),6) knZ<V%/e
Dateadd(mm,datediff(mm,0,getdate()),0) 1uhSP!b
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) i'vjvc~
Dateadd(yy,datediff(yy,0,getdate()),0) 2c<phmiK
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) C/pu]%n@4
上面的SQL代码只是一个时间段 ^kpu9H
Dateadd(wk,datediff(wk,0,getdate()),-1) &]/.=J
Dateadd(wk,datediff(wk,0,getdate()),6) <3Hu(Jx<O
就是表示本周时间段. iD9hqiX&
下面的SQL的条件部分,就是查询时间段在本周范围内的: MMUw+jM4
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) #Y<b'7yJ
而在存储过程中 JTB5#S4W
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) }L*cP;m#
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) KHXnB