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。 q{@P+2<wF
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一、基础 H),RA]S
1、说明:创建数据库 f0FP9t3k
CREATE DATABASE database-name !a[$)c
2、说明:删除数据库 w \DspF
drop database dbname \G3!TwC%
3、说明:备份sql server [B,p,Q"
--- 创建 备份数据的 device 2 `&<bt[g
USE master GZ"/k<~0
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' CWvlr nv
--- 开始 备份 n?Z f/T
BACKUP DATABASE pubs TO testBack Y)OBTX
4、说明:创建新表 M5u_2;3
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..)
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根据已有的表创建新表: ?cxr%`E
A:create table tab_new like tab_old (使用旧表创建新表) 7@~QkTH~y
B:create table tab_new as select col1,col2... from tab_old definition only Y^3)!>
5、说明:删除新表 $_bZA;EMQ
drop table tabname $rTu6(i1
6、说明:增加一个列 6$(0Ty
Alter table tabname add column col type h--45`cE
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。 ucM.Ro=@
7、说明:添加主键: Alter table tabname add primary key(col) ~oFh>9u
说明:删除主键: Alter table tabname drop primary key(col) H9E(\)@
8、说明:创建索引:create [unique] index idxname on tabname(col....) R8uj3!3^
删除索引:drop index idxname `WlH*p)z9
注:索引是不可更改的,想更改必须删除重新建。 *|poxT G
9、说明:创建视图:create view viewname as select statement InN{^uN
删除视图:drop view viewname cD8Ea(
10、说明:几个简单的基本的sql语句 @T/q d>T o
选择:select * from table1 where 范围 GEfY^!F+
插入:insert into table1(field1,field2) values(value1,value2) U2UyN9:6F
删除:delete from table1 where 范围 :iEA UM
更新:update table1 set field1=value1 where 范围 9'X@@6b*'
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! B~rU1Y)
排序:select * from table1 order by field1,field2 [desc] raF]
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总数:select count as totalcount from table1 @Wz%KdXA
求和:select sum(field1) as sumvalue from table1 jYk5~<\k
平均:select avg(field1) as avgvalue from table1 dq2@6xd
最大:select max(field1) as maxvalue from table1 Z>h{`
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最小:select min(field1) as minvalue from table1 yDuq6`R*
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11、说明:几个高级查询运算词 uAT/6@
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A: UNION 运算符 94YA2_f;
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。 Pv[ykrm/
B: EXCEPT 运算符 2_.CX(kI
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。 L?Tu)<Mn
C: INTERSECT 运算符 kz_M;h>
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。 kkL(;H:%
注:使用运算词的几个查询结果行必须是一致的。 ]7l{g9?ZtV
12、说明:使用外连接 (QKsB3X
A、left outer join: {RJ52Gx(
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&K~!*
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 ( mt*y]p?
B:right outer join: )WclV~
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。 i=V-@|Z
C:full outer join: zg)|rm
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。 d^y86pq.
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二、提升 X7b!;%3@
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) |
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法一:select * into b from a where 1<>1 L,
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法二:select top 0 * into b from a S<9gyW
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ;xI0\a7
insert into b(a, b, c) select d,e,f from b; _^-D _y
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) s_S$7N`ocS
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 G4O3h Y.`
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. lm!FM`m
4、说明:子查询(表名1:a 表名2:b) ]h0Y8kpd
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) D>S8$]^Dm
5、说明:显示文章、提交人和最后回复时间 '?b\F~$8
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b <a fO 6?`
6、说明:外连接查询(表名1:a 表名2:b) ~7dF/Nn5
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c oHk27U G
7、说明:在线视图查询(表名1:a ) [)0
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select * from (SELECT a,b,c FROM a) T where t.a > 1; y%FYXwR{
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 gz#+
select * from table1 where time between time1 and time2 ;)P5#S!n-
select a,b,c, from table1 where a not between 数值1 and 数值2 @H6%G>K,
9、说明:in 的使用方法 m$)YYpX
select * from table1 where a [not] in ('值1','值2','值4','值6') 1NW>wo
10、说明:两张关联表,删除主表中已经在副表中没有的信息 >I|<^$/
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) R7,pukK
11、说明:四表联查问题: UL[uh@4
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 ..... z41D^}b
12、说明:日程安排提前五分钟提醒 AT-0}9z{
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 lqauk)(A0
13、说明:一条sql 语句搞定数据库分页 8'n#O>V@
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 HMhLTl{;
14、说明:前10条记录 !@A|L#*
select top 10 * form table1 where 范围 ps"9;4P
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.) Vl-D<M+ih
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ig+k[`W
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 2G H)iUmc
(select a from tableA ) except (select a from tableB) except (select a from tableC) :)j7U3u
17、说明:随机取出10条数据 |K6nOX!i
select top 10 * from tablename order by newid() qR_SQ
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18、说明:随机选择记录 &hO$4q tN
select newid() 0:jsV|5B8
19、说明:删除重复记录 =I7[L{+~Y
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) L-j/R1fTvl
20、说明:列出数据库里所有的表名 y>4p~
select name from sysobjects where type='U' 7WXiG0
21、说明:列出表里的所有的 (&k')ff9K
select name from syscolumns where id=object_id('TableName') .a5X*M]
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 s* @QT8%
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type ?,!uA)({n
显示结果: 4_WH
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type vender pcs v [dAywW
电脑 A 1 _@7(g(pY 3
电脑 A 1 { qjUI
光盘 B 2 1]HHe*'Z
光盘 A 2 Un]DFu
手机 B 3 6<#Slw[
手机 C 3 LMt0'Ml9
23、说明:初始化表table1 rYD']%2
TRUNCATE TABLE table1 4a#B!xW
24、说明:选择从10到15的记录 A (PE
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc n&(3o6i'
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三、技巧
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1、1=1,1=2的使用,在SQL语句组合时用的较多 t`h_+p%>
"where 1=1" 是表示选择全部 "where 1=2"全部不选, Sb^a dd0dT
如: `Yg7,{A\J
if @strWhere !='' \MF3CK@/
begin JATS6-Lz`
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere .V7Y2!4TE
end t$tsWAmiA[
else '
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begin u<x[5xH+
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' j)<;g(
end Fka1]|j9
我们可以直接写成 k>7gy?Y!K<
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ^
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2、收缩数据库 NJ.rv
--重建索引 Cm9 9?K
DBCC REINDEX *sjj"^'=
DBCC INDEXDEFRAG /j`i/Ha1
--收缩数据和日志 xV"6d{+
DBCC SHRINKDB z]'|nX
DBCC SHRINKFILE qn5yD!1
3、压缩数据库 5w]DncdQ~
dbcc shrinkdatabase(dbname) #8P#^v]H
4、转移数据库给新用户以已存在用户权限 lp IteZw:
exec sp_change_users_login 'update_one','newname','oldname' )e@01l
go Z|V"8jE
5、检查备份集 MA~|y_V
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' H(
6、修复数据库 =1%zI%
ALTER DATABASE [dvbbs] SET SINGLE_USER
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GO f6keWqv<GW
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK
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GO %@M00~-
ALTER DATABASE [dvbbs] SET MULTI_USER AGw1Pl8]K
GO EGp~Vo-
7、日志清除 WZfk}To1#
SET NOCOUNT ON nF|#@O`1
DECLARE @LogicalFileName sysname, 67Af} >Q
@MaxMinutes INT, )->-~E}p9
@NewSize INT j<`I\Pmv
USE tablename -- 要操作的数据库名 ls8olLM>
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 e[d7UV[Knn
@MaxMinutes = 10, -- Limit on time allowed to wrap log. Zkwy.Hq^
@NewSize = 1 -- 你想设定的日志文件的大小(M) 2+c>O%L
-- Setup / initialize .6lY*LI
DECLARE @OriginalSize int Y&ct+w]%
SELECT @OriginalSize = size ujI 3tsl
FROM sysfiles u5[1Z|O
WHERE name = @LogicalFileName ?^+#pcX]t|
SELECT 'Original Size of ' + db_name() + ' LOG is ' +
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CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + X
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CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' GC5#1+fQ
FROM sysfiles jKY Aid{-
WHERE name = @LogicalFileName L%c]%3A
CREATE TABLE DummyTrans 8:3oH!n
(DummyColumn char (8000) not null) 9,Crmbw8
DECLARE @Counter INT, @lb=-oR!~
@StartTime DATETIME, pgLzFY['
@TruncLog VARCHAR(255) >S?C {_g
SELECT @StartTime = GETDATE(), M"$jpBN*
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' pfJVE
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 3Hb .ZLE#
EXEC (@TruncLog) pIU#c&%<9
-- Wrap the log if necessary. (%ri#r
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired r'mnkg2,
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) _qO;{%r
AND (@OriginalSize * 8 /1024) > @NewSize 1C5kS[!
BEGIN -- Outer loop. qaCi)f!Dl
SELECT @Counter = 0 !`O_VV`/@
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 1 $KLMW
BEGIN -- update 0-;DN:>
INSERT DummyTrans VALUES ('Fill Log') Lz#$_Am'H
DELETE DummyTrans e')&ODQ H
SELECT @Counter = @Counter + 1 ?<>,XyY
END X:xC>4]gG'
EXEC (@TruncLog) D7gX,e
END Knw'h;,[
SELECT 'Final Size of ' + db_name() + ' LOG is ' + _D7HQ
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + H3UX{|[
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' L.I}-n
FROM sysfiles 34++Rr [G
WHERE name = @LogicalFileName g%fJyk'
DROP TABLE DummyTrans B
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SET NOCOUNT OFF q N[\J7Pz9
8、说明:更改某个表 zd6Qw-D7x
exec sp_changeobjectowner 'tablename','dbo' "tg\yem
9、存储更改全部表 PpJE|[]
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch aOAwezfYR
@OldOwner as NVARCHAR(128), ^2Fs)19R
@NewOwner as NVARCHAR(128) &2<&X( )
AS !~w6"%2+7
DECLARE @Name as NVARCHAR(128) N%n1>!X)!
DECLARE @Owner as NVARCHAR(128) #+k.b_LS
DECLARE @OwnerName as NVARCHAR(128) &}L36|A:
DECLARE curObject CURSOR FOR Eezlx9b
select 'Name' = name, $Z(g=nS>
'Owner' = user_name(uid) )\I? EU8
from sysobjects Up!ZCZ$RC
where user_name(uid)=@OldOwner <x>k3bD
order by name 5m%baf2_
OPEN curObject
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FETCH NEXT FROM curObject INTO @Name, @Owner ]"2 v7)e
WHILE(@@FETCH_STATUS=0) 3 -_U-:2"
BEGIN :xAe<Pq
if @Owner=@OldOwner Z)6nu)
begin ZB_16&2Ow
set @OwnerName = @OldOwner + '.' + rtrim(@Name) **w*hd]
exec sp_changeobjectowner @OwnerName, @NewOwner W O+?gu
end #<WyId(
-- select @name,@NewOwner,@OldOwner 5u
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FETCH NEXT FROM curObject INTO @Name, @Owner 3wa<,^kqy
END r:8]\RU
close curObject ]\os`At
deallocate curObject :>er^\
GO \0^r J1*
10、SQL SERVER中直接循环写入数据 t7*H8
declare @i int Hq"<vp
set @i=1 _A~~L6C
while @i<30 v,!Y=8~9
begin s:m<(8WRw
insert into test (userid) values(@i) tsSS31cv
set @i=@i+1 eN2k8=
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 2XecP'+m
Dateadd(wk,datediff(wk,0,getdate()),-1) <p L;-
Dateadd(wk,datediff(wk,0,getdate()),6) J.1ln
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Dateadd(mm,datediff(mm,0,getdate()),0) ^b `>/>
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ~d#;r5>
Dateadd(yy,datediff(yy,0,getdate()),0) 8H%I|fm
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) asmW
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上面的SQL代码只是一个时间段 thZ@BrO#
Dateadd(wk,datediff(wk,0,getdate()),-1) d'x<F[`O
Dateadd(wk,datediff(wk,0,getdate()),6) "e7$q&R
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就是表示本周时间段. F)<G]i8n~
下面的SQL的条件部分,就是查询时间段在本周范围内的: h2/1S{/n]
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) hOrk^iYN=
而在存储过程中 +k(3+b$S-
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) xn x1`|1u
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) ]\9B?W(#