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。 YPGzI]\
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一、基础 #O!2
1、说明:创建数据库 Pj]^p{>
CREATE DATABASE database-name R.*;] R>M
2、说明:删除数据库 |'1.ajxw
drop database dbname ]7cciob
3、说明:备份sql server xjiV9{w
--- 创建 备份数据的 device Pg8boN]}
USE master vD9\i*\2
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 9#9bm
--- 开始 备份 ?g{[U0)
BACKUP DATABASE pubs TO testBack yna!L@ *@,
4、说明:创建新表 /KWdIP#
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) (J %4}Dm
根据已有的表创建新表: |f @A-d X
A:create table tab_new like tab_old (使用旧表创建新表) D.:`]W|
B:create table tab_new as select col1,col2... from tab_old definition only x}pH'S7
5、说明:删除新表 >oWPwXA
drop table tabname S+~;PmN9qL
6、说明:增加一个列 MymsDdQ]
Alter table tabname add column col type ]o]`X$n
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。 $(;Ts)P
7、说明:添加主键: Alter table tabname add primary key(col) 5I2 h(Td
说明:删除主键: Alter table tabname drop primary key(col) z^`4n_(Ygu
8、说明:创建索引:create [unique] index idxname on tabname(col....) &WBpd}|+Y
删除索引:drop index idxname F?R6zvive
注:索引是不可更改的,想更改必须删除重新建。 ;"0bVs`.^e
9、说明:创建视图:create view viewname as select statement M&V4|D
删除视图:drop view viewname EBW*v '
10、说明:几个简单的基本的sql语句 d;p3cW"
选择:select * from table1 where 范围 Yg '(
插入:insert into table1(field1,field2) values(value1,value2) `Wjq$*
删除:delete from table1 where 范围 .eg'Z@o
更新:update table1 set field1=value1 where 范围 _g/d/{-{Q
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! Bj2iYk_cLa
排序:select * from table1 order by field1,field2 [desc] )cRHt:
总数:select count as totalcount from table1 r3U7`P
求和:select sum(field1) as sumvalue from table1 W|@SXO)DY
平均:select avg(field1) as avgvalue from table1 O0z-jZ,])
最大:select max(field1) as maxvalue from table1 {CR`~)v&
最小:select min(field1) as minvalue from table1 FT~c|ep.
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11、说明:几个高级查询运算词 @H$am
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A: UNION 运算符 flqr["czwK
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 D9NRM;v
B: EXCEPT 运算符 G@D;_$a
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。 0 fT*O
C: INTERSECT 运算符 ym6Emf]
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。 Z"Hq{?l9
注:使用运算词的几个查询结果行必须是一致的。 T+P{,,a/]
12、说明:使用外连接 )E=B;.FH
A、left outer join: B&X)bGx8
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。 2& Hl
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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 DL~!
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B:right outer join: 2 N &B
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。 Et*LbU
C:full outer join: gsQn@(;
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。 E{JTy{z-
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二、提升 teDRX13=;
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) wjX0r7^@
法一:select * into b from a where 1<>1 ._x"b5C
法二:select top 0 * into b from a sOWP0xY
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) :jTbzDqQ
insert into b(a, b, c) select d,e,f from b; qfFa" a
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) Lp$&eROFVs
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 502(CO>
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ]A-LgDsS
4、说明:子查询(表名1:a 表名2:b) kp[&SKU
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select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) 6@^
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5、说明:显示文章、提交人和最后回复时间 S?v;+3TG
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b /P3Pv"r|8]
6、说明:外连接查询(表名1:a 表名2:b) b9.7j!W
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c GPs4:CIgG
7、说明:在线视图查询(表名1:a ) nrpbQ(zI*
select * from (SELECT a,b,c FROM a) T where t.a > 1; l3MA&&++KF
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 ZyC[w7$I2
select * from table1 where time between time1 and time2 ,bzgjw+R5
select a,b,c, from table1 where a not between 数值1 and 数值2 iuEe#B;!
9、说明:in 的使用方法 -y&>&D
select * from table1 where a [not] in ('值1','值2','值4','值6') x51p'bNy
10、说明:两张关联表,删除主表中已经在副表中没有的信息 <Vyl*a{%
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) QB*AQ5-
11、说明:四表联查问题: =}0>S3a.7
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 ..... 3WkrG.$[b
12、说明:日程安排提前五分钟提醒 :8)3t! A
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ezJ^
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13、说明:一条sql 语句搞定数据库分页 f]Z9=
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 uX7"u*@Q*~
14、说明:前10条记录 y>UQm|o<W
select top 10 * form table1 where 范围 %kBrxf
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.) Cq=k3d#}
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) O'~^wu.
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 QE;,mC>
(select a from tableA ) except (select a from tableB) except (select a from tableC) i}:^<jDv?
17、说明:随机取出10条数据 r)qow.+&
select top 10 * from tablename order by newid() m:;`mBOc3
18、说明:随机选择记录 g( eA?
select newid() M|z4Dy
19、说明:删除重复记录 G8W^XD
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 5X-d,8{w
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20、说明:列出数据库里所有的表名 GV)DLHiyxX
select name from sysobjects where type='U' y7R{6W_U>
21、说明:列出表里的所有的 n)]u|qq
select name from syscolumns where id=object_id('TableName') J72kjj&C
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。 W6*5e{
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 ]mO7O+
显示结果: UUgc>
type vender pcs $kQQdF
电脑 A 1 t_X=x`f
电脑 A 1 QN~9O^
光盘 B 2 &ujq6~#
光盘 A 2 60p*4>^v
手机 B 3 98l-
手机 C 3 ^zS|O]Tx
23、说明:初始化表table1 (TGG?V
TRUNCATE TABLE table1 VelX+|w
24、说明:选择从10到15的记录 #5IfF~*i
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ;&RHc#1F
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三、技巧 2I~a{:O
1、1=1,1=2的使用,在SQL语句组合时用的较多 iJ`v3PP
"where 1=1" 是表示选择全部 "where 1=2"全部不选, =G/`r!r*0I
如: /u'M7R
if @strWhere !='' ~c
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begin *3Ci4\Ew
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere .sPa${
end Je~Ybh
else +Xr87x;
begin 0(!=N1l
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' u#34mg..
end mt3j$r{_
我们可以直接写成 &f>1/"lnd\
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere jP"='6Vrw
2、收缩数据库 2Yd;#i)
--重建索引 IY9##&c3>
DBCC REINDEX ww{07g
DBCC INDEXDEFRAG (V+iJ_1g{
--收缩数据和日志 v4x1=E
DBCC SHRINKDB SE!0f&
DBCC SHRINKFILE J{5&L &4
3、压缩数据库 m3K .\3
dbcc shrinkdatabase(dbname) XF N4m #
4、转移数据库给新用户以已存在用户权限 olf7L%
exec sp_change_users_login 'update_one','newname','oldname' k39;7J
go -r"h[UV)
5、检查备份集 A 4|a{\|$
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' zINziAp{
6、修复数据库 tqe8:\1yK
ALTER DATABASE [dvbbs] SET SINGLE_USER 41`&/9:"_M
GO "@)9$-g
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK u~^d5["T
GO /F6=iHK(l
ALTER DATABASE [dvbbs] SET MULTI_USER onAC;<w
GO @5\ns-%
7、日志清除 U
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SET NOCOUNT ON pO_L,~<
DECLARE @LogicalFileName sysname, L2
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@MaxMinutes INT, :CAbGs:56
@NewSize INT ~<#!yRy>r
USE tablename -- 要操作的数据库名 ]p2M!N,?
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 GE[J`?E]
@MaxMinutes = 10, -- Limit on time allowed to wrap log. m2"~.iM8
@NewSize = 1 -- 你想设定的日志文件的大小(M) 7Z<ba^r}
-- Setup / initialize ^8yhx-mgb
DECLARE @OriginalSize int Jk!*j
SELECT @OriginalSize = size Ui`Z>,0sFi
FROM sysfiles r|tTDKGQ
WHERE name = @LogicalFileName iv/!c Mb
SELECT 'Original Size of ' + db_name() + ' LOG is ' + /Z*XKIU6v/
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + tk
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CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' "R/Xv+;
FROM sysfiles Z>H
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WHERE name = @LogicalFileName kW@,P.88
CREATE TABLE DummyTrans +MfdZD
(DummyColumn char (8000) not null) #A2)]XvY
DECLARE @Counter INT, %kJ_o*"
@StartTime DATETIME, g"iLhm`L
@TruncLog VARCHAR(255) A<VNttgG
SELECT @StartTime = GETDATE(), ,1+)qv#|i
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' o4"7i 9+g
DBCC SHRINKFILE (@LogicalFileName, @NewSize) >f$>Odqe
EXEC (@TruncLog) ED={OZD8
-- Wrap the log if necessary. uxd5 XS
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 75LIQ!G|=
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) VSlIeZ
AND (@OriginalSize * 8 /1024) > @NewSize _cY!\'
BEGIN -- Outer loop. #X(KW&;m
SELECT @Counter = 0 1 f;k)x
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) D^knN-nZ*
BEGIN -- update Q~A25Jf.
INSERT DummyTrans VALUES ('Fill Log') S6r$n
DELETE DummyTrans ;r_YEPlZ
SELECT @Counter = @Counter + 1 Wa{>R2h\
END xmEmdOoD
EXEC (@TruncLog) yqm^4)Dp
END 2,Og(_0>
SELECT 'Final Size of ' + db_name() + ' LOG is ' + Ck|3DiRQ
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ~EVD NnHEr
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' f"j"ZM{~U
FROM sysfiles y%21`y&Os
WHERE name = @LogicalFileName xi.L?"^/!
DROP TABLE DummyTrans .'q0*Pe
SET NOCOUNT OFF ]iyJ>fC
8、说明:更改某个表 Q}N.DM@d3
exec sp_changeobjectowner 'tablename','dbo' >+w(%;i;
9、存储更改全部表 PyD'lsV
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch :1eJc2o
@OldOwner as NVARCHAR(128), s\6kXR
@NewOwner as NVARCHAR(128) 4{h?!Z*
AS $\|$ekil4
DECLARE @Name as NVARCHAR(128) 8v},&rhPQq
DECLARE @Owner as NVARCHAR(128) <wt#m`Za
DECLARE @OwnerName as NVARCHAR(128) Sxrbhnx
DECLARE curObject CURSOR FOR "0F =txduS
select 'Name' = name, ]}_@!F)
'Owner' = user_name(uid) =#AeOqs( q
from sysobjects G] -$fz
where user_name(uid)=@OldOwner (=d%Bn$6b
order by name P~V0<$C
OPEN curObject ]OE{qXr{
FETCH NEXT FROM curObject INTO @Name, @Owner c5?;^a[
WHILE(@@FETCH_STATUS=0) ZE@!s3\
BEGIN .D^=vuxt~
if @Owner=@OldOwner ;IC :]Zu
begin xr uQ=Q
set @OwnerName = @OldOwner + '.' + rtrim(@Name) mX)UoiXue
exec sp_changeobjectowner @OwnerName, @NewOwner Q7X6OFl?
end M+X>!Os
-- select @name,@NewOwner,@OldOwner \dAh^B K1(
FETCH NEXT FROM curObject INTO @Name, @Owner jlV~-}QKb7
END {%$eq{~m
close curObject w`(EW>i
deallocate curObject 36154*q
GO pJC@}z^cw
10、SQL SERVER中直接循环写入数据 ^mLZT*
declare @i int NGD?.^ (G
set @i=1 bE-{
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while @i<30 ?u/Uov@rD
begin VjbRjn5LI
insert into test (userid) values(@i)
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set @i=@i+1 >5{Z'UWxh
end Y%v?ROql
小记存储过程中经常用到的本周,本月,本年函数 =@U~sl[
Dateadd(wk,datediff(wk,0,getdate()),-1) U[/k=}76
Dateadd(wk,datediff(wk,0,getdate()),6) sgdxr!1?y
Dateadd(mm,datediff(mm,0,getdate()),0) };[~>Mzl
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) x:W nF62
Dateadd(yy,datediff(yy,0,getdate()),0) (|_1ku3!
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) <0OZ9?,dm
上面的SQL代码只是一个时间段 <StyO[
Dateadd(wk,datediff(wk,0,getdate()),-1) sW[8f
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Dateadd(wk,datediff(wk,0,getdate()),6) c <8s\2
就是表示本周时间段. S}Wj+H;
下面的SQL的条件部分,就是查询时间段在本周范围内的: &n>\ +Q
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) CO e"te
而在存储过程中 6/ir("LK
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) TAbd[:2{F
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) <]6])f,y\