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。 ,
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一、基础 Vuz!~kLYIn
1、说明:创建数据库 orL7y&w(v:
CREATE DATABASE database-name Vxk0oIk`
2、说明:删除数据库 1lx\Pz@ol
drop database dbname rfCoi>{<
3、说明:备份sql server DpTQP u9
--- 创建 备份数据的 device RNIfw1R
USE master k"L_0HK
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' X|.X4fs
--- 开始 备份 Ob(j_{m
BACKUP DATABASE pubs TO testBack $x`U)pv
4、说明:创建新表 zM)o^Fn2
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) '9RHwKu&s
根据已有的表创建新表: ~%GUc
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A:create table tab_new like tab_old (使用旧表创建新表) xi|iV1A
B:create table tab_new as select col1,col2... from tab_old definition only NP|U
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5、说明:删除新表 ,rTR
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drop table tabname 9N-mIGJ
6、说明:增加一个列 0eb`9yM
Alter table tabname add column col type UkeW2l`:
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。 6%:'2;xM
7、说明:添加主键: Alter table tabname add primary key(col) c.d*DM}W
说明:删除主键: Alter table tabname drop primary key(col) ]bX.w/=
8、说明:创建索引:create [unique] index idxname on tabname(col....) Ak4iG2
删除索引:drop index idxname i@d!g"tot
注:索引是不可更改的,想更改必须删除重新建。 {zg}KiNDZd
9、说明:创建视图:create view viewname as select statement 2M|jWy _
删除视图:drop view viewname
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10、说明:几个简单的基本的sql语句 |@Z
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选择:select * from table1 where 范围 GL
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插入:insert into table1(field1,field2) values(value1,value2) ^yBx.GrQc
删除:delete from table1 where 范围 TrHBbyqk
更新:update table1 set field1=value1 where 范围 }.e*=/"MB
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! b%pLjvU
排序:select * from table1 order by field1,field2 [desc] ^8We}bs-c
总数:select count as totalcount from table1 =(@J+Ou
求和:select sum(field1) as sumvalue from table1 Z/a]oR@
平均:select avg(field1) as avgvalue from table1 :a`l_RMU
最大:select max(field1) as maxvalue from table1 5)EnOT"'
最小:select min(field1) as minvalue from table1 S* <:He&1
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11、说明:几个高级查询运算词 zJtYy4jI)
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A: UNION 运算符 }X}fX#[
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。 Rrk3EL
B: EXCEPT 运算符 G?YKm1:w
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。 B;_M52-B
C: INTERSECT 运算符 ^bS&[+9E
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。 ?1 ?m4i
注:使用运算词的几个查询结果行必须是一致的。 M-0BQs`N
12、说明:使用外连接 pGUrYik4
A、left outer join: o- GHAQ
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。 Tpkm\_
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 -YRF^72+
B:right outer join: P>jlFm
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。 IDwneFO
C:full outer join: Pm
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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。 u9}=g%TV
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二、提升 qI KVu_
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) LLV:E{`p
法一:select * into b from a where 1<>1 >CNH=
法二:select top 0 * into b from a \$GlB+ iCx
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) m!w(Q+*j
insert into b(a, b, c) select d,e,f from b; >a@-OJ.yOk
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) D0tI
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 bi[vs|
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ;/
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4、说明:子查询(表名1:a 表名2:b) 1;g>?18@
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) ;h3c+7u1
5、说明:显示文章、提交人和最后回复时间 l.Qj?G
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b QFN 9j
6、说明:外连接查询(表名1:a 表名2:b) m6H+4@Z-;(
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ;j[gE
7、说明:在线视图查询(表名1:a ) &~x |w6M]J
select * from (SELECT a,b,c FROM a) T where t.a > 1; `Fe/=]<$
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 "vkM*HP
select * from table1 where time between time1 and time2 3q@H8%jcw
select a,b,c, from table1 where a not between 数值1 and 数值2 WX`wz>KK^
9、说明:in 的使用方法 -UAMHd}4
select * from table1 where a [not] in ('值1','值2','值4','值6') =h?%<2t9<
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ^y93h8\y
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) hOV5WO\
11、说明:四表联查问题: 1W-kZ(e
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 ..... w@YPG{"j
12、说明:日程安排提前五分钟提醒 F x$W3FIO]
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 > PL}7f&:
13、说明:一条sql 语句搞定数据库分页 cRCji^,KJ
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 D vN0h(?
14、说明:前10条记录 %U.x9UL
select top 10 * form table1 where 范围 M\Wg|gpy
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) n:?a=xY
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) +# !?+'A
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 G=CP17&h6
(select a from tableA ) except (select a from tableB) except (select a from tableC) /}%C'
17、说明:随机取出10条数据 9Uz2j$p7
select top 10 * from tablename order by newid() 1N{ >00
18、说明:随机选择记录 1Mx2%
select newid() /?|;f2tbV2
19、说明:删除重复记录
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Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) V' i@N
20、说明:列出数据库里所有的表名 .lI.I
select name from sysobjects where type='U' 1gvh6eE
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21、说明:列出表里的所有的 yFDt%&*n^
select name from syscolumns where id=object_id('TableName') xa
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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。 &Ot9"Aq:
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 8{7'w|/;.{
显示结果: up~p_{x)Q
type vender pcs .%\||1F<
电脑 A 1 w*(1qUF#%
电脑 A 1 Lm0q/d2|\X
光盘 B 2 0&Iu+hv
光盘 A 2 O -p^S
手机 B 3 o?3C -A|
手机 C 3 !HW?/-\,O
23、说明:初始化表table1 b`cH.v
TRUNCATE TABLE table1 |h((SreO
24、说明:选择从10到15的记录 hsQ*ozv[)
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc q%1B4 mF'
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三、技巧 g`"_+x'
1、1=1,1=2的使用,在SQL语句组合时用的较多 mhs%8OTN
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 9IacZ
如: Gq?>Bi;`
if @strWhere !='' <4;L&3
begin 6HpiG`
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere =jU#0FAO
end `YBHBTG'o!
else 7Fb!;W#X
begin xP'"!d4^i
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' nv:VX{%
end )Oj{x0{\Q
我们可以直接写成 A{DE7gp!
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere WxtB:7J
2、收缩数据库 1ZWr@,\L
--重建索引 P4s,N|bs`
DBCC REINDEX TLz>|gr
DBCC INDEXDEFRAG _o>?\ :A
--收缩数据和日志 0!1cHB/c
DBCC SHRINKDB N'%l/
DBCC SHRINKFILE 8J2UUVA`1
3、压缩数据库 LD}<|
dbcc shrinkdatabase(dbname) ksAu=X:
4、转移数据库给新用户以已存在用户权限 0qN+W&H
exec sp_change_users_login 'update_one','newname','oldname' TO]
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go KFM)*Icg\8
5、检查备份集 ^F|/\i
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' a7laCHI
6、修复数据库 QnIF{TS=
ALTER DATABASE [dvbbs] SET SINGLE_USER (Lkcx06e
GO ^4a|gc
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK q]P$NeEiZ"
GO v)v`896S`
ALTER DATABASE [dvbbs] SET MULTI_USER QU)AgF[
GO T2XLP
7、日志清除 ;k,#o!>
SET NOCOUNT ON 9aY}+hgb#
DECLARE @LogicalFileName sysname, p8E6_%Rw
@MaxMinutes INT, 2nB{oF-Z
@NewSize INT H\=S_b1wo
USE tablename -- 要操作的数据库名 hoZM;wC
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 7JLjA\k
@MaxMinutes = 10, -- Limit on time allowed to wrap log. #pWeMt'
@NewSize = 1 -- 你想设定的日志文件的大小(M) #]s&[O43
-- Setup / initialize B>e},!
DECLARE @OriginalSize int e>b|13X
SELECT @OriginalSize = size
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FROM sysfiles b3+F~G-I"
WHERE name = @LogicalFileName
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SELECT 'Original Size of ' + db_name() + ' LOG is ' + o/I`L
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + `"eIzLc%o6
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' |@pn=wW
FROM sysfiles x:`"tJa
WHERE name = @LogicalFileName %xP'*EaM?
CREATE TABLE DummyTrans rSNaflYAr
(DummyColumn char (8000) not null) /jd.<r=_I
DECLARE @Counter INT, q,.@<s W
@StartTime DATETIME, e!1am%aE
@TruncLog VARCHAR(255) &h;J_Ps
SELECT @StartTime = GETDATE(), ~L=? F
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ^eCMATE
DBCC SHRINKFILE (@LogicalFileName, @NewSize) _F tI2G9
EXEC (@TruncLog) =~'{2gsB
-- Wrap the log if necessary. ^ <+V[=X
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired O|Y~^:ny
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) I_iXu;UX
AND (@OriginalSize * 8 /1024) > @NewSize 7H_*1_%ZQ
BEGIN -- Outer loop. &K-0ld(;
SELECT @Counter = 0 i-`J+8|d
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) h)sQ3B.}A
BEGIN -- update K&TO8
INSERT DummyTrans VALUES ('Fill Log') !)LVZfQ0
DELETE DummyTrans DkeFDzQ5
SELECT @Counter = @Counter + 1 0yBiio
END QK(w2`
EXEC (@TruncLog) ^;.&=3N,+
END )|E617g
SELECT 'Final Size of ' + db_name() + ' LOG is ' + #A9rI;"XI
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ZoT8
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 6"u"B-cz
FROM sysfiles O
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WHERE name = @LogicalFileName Ae_:Kc6
DROP TABLE DummyTrans a0
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SET NOCOUNT OFF dNT<![X\
8、说明:更改某个表 oS#PBql4
exec sp_changeobjectowner 'tablename','dbo' 5PPaR|c3
9、存储更改全部表 rtZEK:.#
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch }MW+K&sIh
@OldOwner as NVARCHAR(128), &W$s-qf".
@NewOwner as NVARCHAR(128) +$
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AS +9R@cUr
DECLARE @Name as NVARCHAR(128) <@J0
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DECLARE @Owner as NVARCHAR(128) Q>
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DECLARE @OwnerName as NVARCHAR(128) cOvdC4
DECLARE curObject CURSOR FOR :L5k#E"u
select 'Name' = name, X@H/"B%u2
'Owner' = user_name(uid) 4-JyK%m,0
from sysobjects =RjseTS
where user_name(uid)=@OldOwner `xF^9;5mi
order by name 0vrx5E!
OPEN curObject EdC/]
FETCH NEXT FROM curObject INTO @Name, @Owner V&Q_iE
WHILE(@@FETCH_STATUS=0) Fu[<zA^
BEGIN /SD(g@G,
if @Owner=@OldOwner
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begin 7)dCdO
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ,qT+Vqpr{
exec sp_changeobjectowner @OwnerName, @NewOwner ^~JF7u
end 8\Kpc;zb
-- select @name,@NewOwner,@OldOwner Y>SpV_H%
FETCH NEXT FROM curObject INTO @Name, @Owner >Q[3t79^
END 1Ms_2
close curObject T*jQzcm~?
deallocate curObject NY"+Qw@$
GO (DY&{vudF
10、SQL SERVER中直接循环写入数据 kV@?Oj.&I,
declare @i int /|>?!;
set @i=1 DAf0bh"
while @i<30 BD?u|Fd,i:
begin Wg\MaZ6Di
insert into test (userid) values(@i) aI_[h
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set @i=@i+1 _t?#
end tui5?\
小记存储过程中经常用到的本周,本月,本年函数 AwWo,Y399h
Dateadd(wk,datediff(wk,0,getdate()),-1) '9@AhiNV
Dateadd(wk,datediff(wk,0,getdate()),6) N^f_hL|:9
Dateadd(mm,datediff(mm,0,getdate()),0) YT'olk
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) p9![8VU
Dateadd(yy,datediff(yy,0,getdate()),0) /z`.- D(
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) pch8A0JAl)
上面的SQL代码只是一个时间段 r`i.h ^2De
Dateadd(wk,datediff(wk,0,getdate()),-1) vAjog])9s
Dateadd(wk,datediff(wk,0,getdate()),6) *;T'=u_lR
就是表示本周时间段. >M^:x-mib
下面的SQL的条件部分,就是查询时间段在本周范围内的: uK0L>
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) P MI?PC[;
而在存储过程中 ,YRBYK:
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) $."Fz
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select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) =&PO_t5)z