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。 m?0caLw<
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一、基础 ^|gD;OED7O
1、说明:创建数据库 Sjv_% C$
CREATE DATABASE database-name BRyrdt*_e
2、说明:删除数据库 tP^2NTs%]
drop database dbname Z0 @P1
3、说明:备份sql server /'O?
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--- 创建 备份数据的 device nF`_3U8e
USE master =~15q=XY0
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' c<fl6o)
--- 开始 备份 \AQ*T`Dq
BACKUP DATABASE pubs TO testBack B _k+Oa2!
4、说明:创建新表 v4OroG=^
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) #-W
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根据已有的表创建新表: N"L@
A:create table tab_new like tab_old (使用旧表创建新表) 9bwG3jn4?
B:create table tab_new as select col1,col2... from tab_old definition only 8`Ih>
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5、说明:删除新表 QbrR=[8b
drop table tabname [3o^06V8j
6、说明:增加一个列 ,%6!8vX
Alter table tabname add column col type {el[W,CT#
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。 D?A3p6%
7、说明:添加主键: Alter table tabname add primary key(col) h6`v%7H?
说明:删除主键: Alter table tabname drop primary key(col) ]O]6O%.ao
8、说明:创建索引:create [unique] index idxname on tabname(col....) G
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删除索引:drop index idxname WCRGqSr4
注:索引是不可更改的,想更改必须删除重新建。 +`=rzL"0I7
9、说明:创建视图:create view viewname as select statement rrz^LD
删除视图:drop view viewname @kBy|5
10、说明:几个简单的基本的sql语句 o+*7Q!
选择:select * from table1 where 范围 Pg4go10|
插入:insert into table1(field1,field2) values(value1,value2) yzWVUqtXm
删除:delete from table1 where 范围 1)Z4
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更新:update table1 set field1=value1 where 范围 w]1Ltq*g/
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! S+2we
排序:select * from table1 order by field1,field2 [desc] Bre:_>*
总数:select count as totalcount from table1 C( wZjO?N
求和:select sum(field1) as sumvalue from table1 q|h#J}\
平均:select avg(field1) as avgvalue from table1 x`n7D
最大:select max(field1) as maxvalue from table1 +@G#Z3;l!
最小:select min(field1) as minvalue from table1 (}*1,N!#
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11、说明:几个高级查询运算词 jEu-CU#:
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A: UNION 运算符 .:r
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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。 Yc^;?n`x
B: EXCEPT 运算符 6
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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。 vb.}SG>
C: INTERSECT 运算符 }-/oL+j
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。 0(qtn9;=2
注:使用运算词的几个查询结果行必须是一致的。 YUjKOPN
12、说明:使用外连接 OJ?U."Lxm$
A、left outer join: *jC Hv
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。 C:r3z50
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 zt!)7HBo
B:right outer join: =W[M=_0u
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。 ~`yO@f;D
C:full outer join: !(A<
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。 gkhmQd
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二、提升 adY ,Nz
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) %_(X n
法一:select * into b from a where 1<>1 ;.+C
法二:select top 0 * into b from a 9s4>hw@u
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) {iXQUj
insert into b(a, b, c) select d,e,f from b; )6b`1o!7
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) 0g'MFS
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 6qR5A+|;
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. I+eKuWB
4、说明:子查询(表名1:a 表名2:b) pN=>q<]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) <IBWA0A=8a
5、说明:显示文章、提交人和最后回复时间 ROi_k4Fj
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 4OOI$J$Jh
6、说明:外连接查询(表名1:a 表名2:b) ^^z_[Ih
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c `|p8zV
7、说明:在线视图查询(表名1:a ) ;q?WU>c{?
select * from (SELECT a,b,c FROM a) T where t.a > 1; F]GX;<`
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 Ve\.7s
select * from table1 where time between time1 and time2 BN1,R] *;
select a,b,c, from table1 where a not between 数值1 and 数值2 +?'a2pUS
9、说明:in 的使用方法 dnzZ\t>U
select * from table1 where a [not] in ('值1','值2','值4','值6') E>c*A40=.n
10、说明:两张关联表,删除主表中已经在副表中没有的信息 pnpf/T{xpM
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) OE/r0C<&
11、说明:四表联查问题: ,5&
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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 ..... L'HO"EZFj
12、说明:日程安排提前五分钟提醒 h9Tst)iRi
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 *4y0Hq
13、说明:一条sql 语句搞定数据库分页 K!a7Hg
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 {W'{A
14、说明:前10条记录 0ky3rFSh1
select top 10 * form table1 where 范围 1VA%xOURh
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.) m`&6[[)6~
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) Pd+Wb3
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 Ow0( q^H<
(select a from tableA ) except (select a from tableB) except (select a from tableC) U!b~vrr^
17、说明:随机取出10条数据 KBI36=UV
select top 10 * from tablename order by newid() NQx>u
18、说明:随机选择记录 eIcIl2
select newid() ZdJQ9y
19、说明:删除重复记录 "lA8CA
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) x-T7
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20、说明:列出数据库里所有的表名 04c`7[
select name from sysobjects where type='U' G&q@B`I
21、说明:列出表里的所有的 :gM_v?sy
select name from syscolumns where id=object_id('TableName') ts &sr
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。 9w<k1j
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 ~pw%p77)
显示结果: {#N,&?[
type vender pcs H<Zs2DP`
电脑 A 1 N&G;`
电脑 A 1 GrA}T` ]
光盘 B 2 #]2,1dJ
光盘 A 2 RY}:&vWDk
手机 B 3 obK6GG?ZE
手机 C 3 wKE}BO >
23、说明:初始化表table1 W]5sqtF;6
TRUNCATE TABLE table1 [Qn=y/._r
24、说明:选择从10到15的记录 r)gtx!bx
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc uA%cie
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三、技巧 }g"K\x:Z
1、1=1,1=2的使用,在SQL语句组合时用的较多 G(hzW%P
"where 1=1" 是表示选择全部 "where 1=2"全部不选, K7},X01^
如: |?LUt@r;
if @strWhere !='' VrKFpFd
begin YR.f`-<Z
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere Mb+CtI_'
end ]Z>zf]<
else :@,UPc-+
begin 2 W Wr./q
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ]g]~!":
end %(~8a
我们可以直接写成 A}CpyRVCn
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere U=N]XwjVK<
2、收缩数据库 sDS0cc6e
--重建索引 sf,9Ym
DBCC REINDEX pW5PF)([
DBCC INDEXDEFRAG !}J19]\
--收缩数据和日志 R 5Cy%
DBCC SHRINKDB 8 O.5ML{
DBCC SHRINKFILE `cqZ;(^
3、压缩数据库 J1d|L|M
dbcc shrinkdatabase(dbname) &Ui&2EW
4、转移数据库给新用户以已存在用户权限 e
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exec sp_change_users_login 'update_one','newname','oldname' yHxi^D]
go *cc|(EM
5、检查备份集 3&Fqd
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' pJ_>^i=
6、修复数据库 ]Czq
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ALTER DATABASE [dvbbs] SET SINGLE_USER vb2aj!8_?
GO Y#fiJ
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK wi S8S{K5
GO [KsVI.gn
ALTER DATABASE [dvbbs] SET MULTI_USER 0hX@ta[Up
GO ]*\<k
7、日志清除 hJGWa%`
SET NOCOUNT ON Iq(;?_
DECLARE @LogicalFileName sysname, o[>p
@MaxMinutes INT, y0
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@NewSize INT (^= Hq'D
USE tablename -- 要操作的数据库名 (Ek=0;Cr
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 @v=A)L
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 33w(Pw
@NewSize = 1 -- 你想设定的日志文件的大小(M) eo'C)j# U
-- Setup / initialize b*o,re)Dj
DECLARE @OriginalSize int jAOD&@z1
SELECT @OriginalSize = size hP=z<&zb/
FROM sysfiles (N$$N:ac[t
WHERE name = @LogicalFileName G9jlpf5>
SELECT 'Original Size of ' + db_name() + ' LOG is ' + !@@rO--&
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + `*Jw[Bnh8
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' WyJXT.
FROM sysfiles ppPzI,
WHERE name = @LogicalFileName )4bZ;'B5
CREATE TABLE DummyTrans cP[]\r+Kj
(DummyColumn char (8000) not null) }$1Aw%p^
DECLARE @Counter INT, Gq^#.o]
@StartTime DATETIME, ai~JY[
@TruncLog VARCHAR(255) !GBGC|avE
SELECT @StartTime = GETDATE(),
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@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' p>
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DBCC SHRINKFILE (@LogicalFileName, @NewSize) ]@7]mu:oL
EXEC (@TruncLog) eZ
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-- Wrap the log if necessary. K7$Vl"l
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired !FR1yO'd>
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) Yq%D/dU8
AND (@OriginalSize * 8 /1024) > @NewSize t+BLO<
BEGIN -- Outer loop. -g)*v<Fb5
SELECT @Counter = 0 IP+1 :M
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 1@A*Jj[R%
BEGIN -- update 4r>buEU
INSERT DummyTrans VALUES ('Fill Log') ?u8vK<2h
DELETE DummyTrans 1Qgd^o:d
SELECT @Counter = @Counter + 1 0-w^y<\
END ^Sz?c_<2P
EXEC (@TruncLog) d
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END s\i.pd:Q
SELECT 'Final Size of ' + db_name() + ' LOG is ' + Ue0Q| h
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 7Om)uUjU4
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' P;!4 VK
FROM sysfiles QprzlxB
WHERE name = @LogicalFileName <jRs/?1R
DROP TABLE DummyTrans G q
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SET NOCOUNT OFF ]qk/V:H:
8、说明:更改某个表 4 4kb
exec sp_changeobjectowner 'tablename','dbo' P1mPC
9、存储更改全部表 r.;(Kx/M
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 8yc?9&/|
@OldOwner as NVARCHAR(128), zVs|go>F
@NewOwner as NVARCHAR(128) aXefi'!6
AS QZ54Osdl
DECLARE @Name as NVARCHAR(128) yi/jZX
DECLARE @Owner as NVARCHAR(128) i iZK^/P$
DECLARE @OwnerName as NVARCHAR(128) xj!_]XJ^w
DECLARE curObject CURSOR FOR Ctxx.MM
select 'Name' = name, DeTZl+qm1E
'Owner' = user_name(uid) e/h7x\Z
from sysobjects ^6
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where user_name(uid)=@OldOwner _[W`!#"
order by name Epm=&6zf
OPEN curObject 3fJwj}wL
FETCH NEXT FROM curObject INTO @Name, @Owner k6 f;A
WHILE(@@FETCH_STATUS=0) |79!exVMBp
BEGIN
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if @Owner=@OldOwner K*Tvo`
begin (FAd'$lhX}
set @OwnerName = @OldOwner + '.' + rtrim(@Name) {1
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exec sp_changeobjectowner @OwnerName, @NewOwner x 1"ikp}
end {G%!M+n<
-- select @name,@NewOwner,@OldOwner ')w*c
FETCH NEXT FROM curObject INTO @Name, @Owner L%.GKANM
END gaJIc^O
close curObject 3f:I<S7
deallocate curObject N{G+|WmQ
GO [\&Mo]"0
10、SQL SERVER中直接循环写入数据 U<
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declare @i int $V)LGu2(m
set @i=1 (&$|R\W.
while @i<30 ]Zim8^n?`.
begin >9g` 9hB
insert into test (userid) values(@i) 8D:{05
set @i=@i+1 5yQv(<~*G
end , &HZvU&
小记存储过程中经常用到的本周,本月,本年函数 ^"%SHs
Dateadd(wk,datediff(wk,0,getdate()),-1) [@= [<
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Dateadd(wk,datediff(wk,0,getdate()),6) r\"O8\
Dateadd(mm,datediff(mm,0,getdate()),0) u-h3xj
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 9Yowz]')
Dateadd(yy,datediff(yy,0,getdate()),0) k852M^JP
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) [hS?d.D
上面的SQL代码只是一个时间段 QWf)5S
Dateadd(wk,datediff(wk,0,getdate()),-1) 5 b[:B~J
Dateadd(wk,datediff(wk,0,getdate()),6) aM9St!i
就是表示本周时间段. O.E
下面的SQL的条件部分,就是查询时间段在本周范围内的: `B6{y9J6
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 8P!dk5,,O
而在存储过程中 Sh]x`3 ).
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) fwRlqfi
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) d/(=q