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。 wmU0E/{9]
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一、基础 CHJ>{b`O
1、说明:创建数据库 b;GD/UI
CREATE DATABASE database-name {HOy_Fiih
2、说明:删除数据库 3WY$WRv
drop database dbname ?7MqeR4/E
3、说明:备份sql server =Gk/k}1
--- 创建 备份数据的 device &~e$:8+
USE master :_kAl? eJ
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' J;$N{"M
--- 开始 备份 wsU V;S*X%
BACKUP DATABASE pubs TO testBack KvPX=/&Zu
4、说明:创建新表 up'
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) $ (=~r`O+1
根据已有的表创建新表: }!>=|1fY
A:create table tab_new like tab_old (使用旧表创建新表) &PWB,BXv
B:create table tab_new as select col1,col2... from tab_old definition only D]s]"QQ8
5、说明:删除新表 M$Zo.Bl$(
drop table tabname U`|0 jJ
6、说明:增加一个列 (Y%Q|u
Alter table tabname add column col type qT:zEt5
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。 \C^;k%{LV
7、说明:添加主键: Alter table tabname add primary key(col) RW$:9~
说明:删除主键: Alter table tabname drop primary key(col) Xjio Z
8、说明:创建索引:create [unique] index idxname on tabname(col....) q.4A(,
删除索引:drop index idxname x35cW7R}T_
注:索引是不可更改的,想更改必须删除重新建。 LPYbHo3fq
9、说明:创建视图:create view viewname as select statement eP.Vd7ky
删除视图:drop view viewname SJt<+kg
10、说明:几个简单的基本的sql语句 0c^>eq]
选择:select * from table1 where 范围 X[gn+6WB%
插入:insert into table1(field1,field2) values(value1,value2) L6Wt3U`l
删除:delete from table1 where 范围
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更新:update table1 set field1=value1 where 范围 s@hRqGd:
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! D}C,![
排序:select * from table1 order by field1,field2 [desc] bI.t<;
总数:select count as totalcount from table1 ^D`v3d
求和:select sum(field1) as sumvalue from table1 W1B)]IHc
平均:select avg(field1) as avgvalue from table1 KOz(TZ?u
最大:select max(field1) as maxvalue from table1 8X|r4otn4
最小:select min(field1) as minvalue from table1 l7{oi!
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11、说明:几个高级查询运算词 ;Vik5)D2D
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A: UNION 运算符 |t
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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。 %1 vsN-O}8
B: EXCEPT 运算符 C;QAT
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。 jn >d*9u
C: INTERSECT 运算符 #rO8K f
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。 XdLCbY
注:使用运算词的几个查询结果行必须是一致的。 #GDe08rOw
12、说明:使用外连接 {U<xdG
A、left outer join: `U#55k9^5
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。 Z+j\a5d?,
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 `@[c8j7
B:right outer join: 4wd&55=2
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。 +YLejjQ
C:full outer join: zA+~7;7E
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。 ,lA.C%4au~
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二、提升 V7G7&'
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) )irRO 8
法一:select * into b from a where 1<>1 DrnJ;Hi"
法二:select top 0 * into b from a m-^8W[r+_
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) i
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insert into b(a, b, c) select d,e,f from b; )[mwP.T=
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) ay "'#[
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 \I"Z2N>^z
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. R8rfM?"W
4、说明:子查询(表名1:a 表名2:b) \0lnxLA
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) Ev7J+TmXM
5、说明:显示文章、提交人和最后回复时间 mWR4|1(
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b o9xlu.QL{c
6、说明:外连接查询(表名1:a 表名2:b) 2aJS{[
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c Le<wR
7、说明:在线视图查询(表名1:a ) :1t~[-h^
select * from (SELECT a,b,c FROM a) T where t.a > 1; 3d<HN6&U
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 ZxV"(\$n
select * from table1 where time between time1 and time2 .s+aZwTMT
select a,b,c, from table1 where a not between 数值1 and 数值2 Y]]}*8
9、说明:in 的使用方法 pwwH<0[
select * from table1 where a [not] in ('值1','值2','值4','值6') uVzFsgBp
10、说明:两张关联表,删除主表中已经在副表中没有的信息 7eWk7&Xul
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) A)%A!
11、说明:四表联查问题: J!'@ Bd
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 ..... yV_4?nh
12、说明:日程安排提前五分钟提醒 AU-n&uX
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 "qc6=:y}
13、说明:一条sql 语句搞定数据库分页 d*)CT?d&
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 nhIa175'
14、说明:前10条记录 kJWN.
select top 10 * form table1 where 范围 %dQxJMwj
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.) +f*OliMD
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ^c:Fy+fb
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 Z2im@c67{
(select a from tableA ) except (select a from tableB) except (select a from tableC) "D?z
17、说明:随机取出10条数据 +)2s-A f-
select top 10 * from tablename order by newid() `tjH<
18、说明:随机选择记录 *tm0R> ?!
select newid() []a[v%PkG
19、说明:删除重复记录 Ag F,aZU
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) gX0R)spg
20、说明:列出数据库里所有的表名 r$]HIvJD
select name from sysobjects where type='U' u7?$b!hG^C
21、说明:列出表里的所有的 rQ7+q;[J
select name from syscolumns where id=object_id('TableName') P!"&%d
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 6mKjau{r_
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type 5@^ dgq
显示结果: bdGIF'p%
type vender pcs [D*UT#FM
电脑 A 1 K&8dA0i2u2
电脑 A 1 k)TSR5A
光盘 B 2 kcb.Wz~=
光盘 A 2 %W@v2
手机 B 3 }Tf9S<xpq3
手机 C 3 Vp>|hj po
23、说明:初始化表table1 G7N|
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TRUNCATE TABLE table1 sP^R/z|Y
24、说明:选择从10到15的记录 [s&$l G!
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc hKzSgYxP=t
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三、技巧 )T;?^kho
1、1=1,1=2的使用,在SQL语句组合时用的较多 P-ri=E}>
"where 1=1" 是表示选择全部 "where 1=2"全部不选, TDd{.8qf
如: Ok n(pJ0
if @strWhere !='' 2Ry1b+\
begin /z BxJT0
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere rXA*NeA3v
end u]vQ>Uu
else 7O,U?p
begin 61xs%kxb..
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' rk)##)
end 271&i
我们可以直接写成 6M13f@v
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere (PfqRk1Y
2、收缩数据库 >Wz;ySEz
--重建索引 msVOH%wH
DBCC REINDEX @xB*KyUW
DBCC INDEXDEFRAG }#X8@
--收缩数据和日志 It{ ;SKeo
DBCC SHRINKDB A^p[52`
DBCC SHRINKFILE |g=="
3、压缩数据库 qL,tYJ<m%
dbcc shrinkdatabase(dbname) wC5ee:u C%
4、转移数据库给新用户以已存在用户权限 8P=o4lO+
exec sp_change_users_login 'update_one','newname','oldname' C`5
go CZ nOui
5、检查备份集 hGiz)v~
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' b, :QT~g=
6、修复数据库 ~i `>adJ:
ALTER DATABASE [dvbbs] SET SINGLE_USER f%V4pzOc"
GO |Pg@M
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK {#)0EzV6
GO -YsLd 9^4
ALTER DATABASE [dvbbs] SET MULTI_USER Y +Fljr*
GO _cu:aktf2
7、日志清除 ij?
SET NOCOUNT ON IEU^#=n
DECLARE @LogicalFileName sysname, C:Hoq(
@MaxMinutes INT, R9B&dvG
@NewSize INT +"1NC\<*
USE tablename -- 要操作的数据库名 {l |E:>Q2
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 sqW*
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@MaxMinutes = 10, -- Limit on time allowed to wrap log. 23h%
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@NewSize = 1 -- 你想设定的日志文件的大小(M) %Q.&ZhB
-- Setup / initialize ZcaX'5}!S
DECLARE @OriginalSize int F+@5C:<?
SELECT @OriginalSize = size }Q";aU0^
FROM sysfiles 5|1T}Z#;
WHERE name = @LogicalFileName zToq^T
SELECT 'Original Size of ' + db_name() + ' LOG is ' + l&[;rh
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + C*`mM'#
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' uJ6DO#d`P
FROM sysfiles CxfRVL`7
WHERE name = @LogicalFileName A\#iXOd
CREATE TABLE DummyTrans Aj0Tfdxy
(DummyColumn char (8000) not null) 2 aL)
DECLARE @Counter INT, mQY_`&Jq
@StartTime DATETIME, e#E2>Bj;
@TruncLog VARCHAR(255) VqS#waNrx
SELECT @StartTime = GETDATE(), kcQ'$<Mz<
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' FXs*vg`
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 4n4?4BEn
EXEC (@TruncLog) hiUD]5Kp
-- Wrap the log if necessary. 0@EwM
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired D_x+:1(
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 4T=u`3pD7l
AND (@OriginalSize * 8 /1024) > @NewSize kV38`s>+
BEGIN -- Outer loop. N2w"R{) j\
SELECT @Counter = 0 0C>%LJ8r
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ezMI\r6
BEGIN -- update =MvjLh"s
INSERT DummyTrans VALUES ('Fill Log') . Z%{'CC
DELETE DummyTrans 3K_A<j:
SELECT @Counter = @Counter + 1 PTEHP
END f-%NaTI
EXEC (@TruncLog) SXy=<%ed
END t
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + Ovj^IjG-`
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 4)("v-p
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' !=N"vD*
FROM sysfiles fXc m|U,ho
WHERE name = @LogicalFileName d20gf:@BM
DROP TABLE DummyTrans k70|'* Kh
SET NOCOUNT OFF B`
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8、说明:更改某个表 HB7;0yt`:
exec sp_changeobjectowner 'tablename','dbo' 1n@8Kv
9、存储更改全部表 3}/&w\$
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch D#o}cC.
@OldOwner as NVARCHAR(128), 2/0v B>
@NewOwner as NVARCHAR(128) n-%s8aaVf
AS APO>y
DECLARE @Name as NVARCHAR(128) o0pII )v
DECLARE @Owner as NVARCHAR(128) h}xeChw]
DECLARE @OwnerName as NVARCHAR(128) %%4t~XC#
DECLARE curObject CURSOR FOR %wSj%>&-R
select 'Name' = name, *Q,0W:~-
'Owner' = user_name(uid) z-b*D}&
from sysobjects K=,F#kn
where user_name(uid)=@OldOwner 3#TV5+x*"`
order by name GxKqD;;u?=
OPEN curObject M6}3wM*4
FETCH NEXT FROM curObject INTO @Name, @Owner '60 L~`K
WHILE(@@FETCH_STATUS=0) K5XK%Gl"
BEGIN IhA* "
if @Owner=@OldOwner (e[}/hf6
begin 8:/e
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set @OwnerName = @OldOwner + '.' + rtrim(@Name) r3\cp0P;s
exec sp_changeobjectowner @OwnerName, @NewOwner DuOG {
end )'4k|@8|
-- select @name,@NewOwner,@OldOwner #/Eb*2C`b
FETCH NEXT FROM curObject INTO @Name, @Owner W]5USFan
END L*~J%7
close curObject 19j+lCSvH
deallocate curObject 1Tm^
GO T16{_
10、SQL SERVER中直接循环写入数据 /, ! B2
declare @i int kJ Mf
set @i=1 Ba/Yl
while @i<30 g2T -TG'd
begin [!U?}1YQ
insert into test (userid) values(@i) .;*s`t
set @i=@i+1 -
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end wy}k1E'M
小记存储过程中经常用到的本周,本月,本年函数 %!PM&zV
Dateadd(wk,datediff(wk,0,getdate()),-1) 9t#S= DP
Dateadd(wk,datediff(wk,0,getdate()),6) ,Bal
Dateadd(mm,datediff(mm,0,getdate()),0) 3fh8$A
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) &w1P\4?G
Dateadd(yy,datediff(yy,0,getdate()),0) =-}[^u1
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 1Q.\s_2
上面的SQL代码只是一个时间段 XGkkB
Dateadd(wk,datediff(wk,0,getdate()),-1) cwL1/DGDB
Dateadd(wk,datediff(wk,0,getdate()),6) \
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就是表示本周时间段. ~PHB_cyth
下面的SQL的条件部分,就是查询时间段在本周范围内的: |e2be1LD
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) }eRD|1
而在存储过程中 WuZ/C_
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) .k0~Vh2u
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) Z>^pCc\lH