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。 5Z*
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一、基础 fUb1/-}
1、说明:创建数据库 ,]0S4h67
CREATE DATABASE database-name 17e=GL
2、说明:删除数据库 l_^T&xq8
drop database dbname Oamv9RyDvC
3、说明:备份sql server Kg4QT/0VA
--- 创建 备份数据的 device zt7_r`#z
USE master hNH.G(l0
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' x7vq?fP0n
--- 开始 备份 XxmJP5
BACKUP DATABASE pubs TO testBack /yLzDCKn
4、说明:创建新表 aXRv}WO$>k
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) +n@f'a">
根据已有的表创建新表: /)sDnJ1r
A:create table tab_new like tab_old (使用旧表创建新表) *
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B:create table tab_new as select col1,col2... from tab_old definition only 5){tBK|
5、说明:删除新表 zx
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drop table tabname q]F4Lq(
6、说明:增加一个列 qIB>6bv#x
Alter table tabname add column col type x$~3$E
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。 U'rr?,RML
7、说明:添加主键: Alter table tabname add primary key(col) A|2 <A
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说明:删除主键: Alter table tabname drop primary key(col) Q}WL/X5
8、说明:创建索引:create [unique] index idxname on tabname(col....) V]r hr
删除索引:drop index idxname 9Tqo LX
注:索引是不可更改的,想更改必须删除重新建。 +#0~:&!9
9、说明:创建视图:create view viewname as select statement u@AI&[Z
删除视图:drop view viewname 7raSf&{&6b
10、说明:几个简单的基本的sql语句 BTOA &Ag
选择:select * from table1 where 范围 0Xp
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插入:insert into table1(field1,field2) values(value1,value2) %_>Tcm=
删除:delete from table1 where 范围 1#/6r :
更新:update table1 set field1=value1 where 范围 x:p}w[WM
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! DP|TIt ,Rl
排序:select * from table1 order by field1,field2 [desc] ,Qat
总数:select count as totalcount from table1 ,oBlJvm
求和:select sum(field1) as sumvalue from table1 :aHcPc:
平均:select avg(field1) as avgvalue from table1 =.DTR5(_h
最大:select max(field1) as maxvalue from table1 l+t #"3
最小:select min(field1) as minvalue from table1 ;?0_Q3IML
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11、说明:几个高级查询运算词 I"B8_
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A: UNION 运算符 xtOx|FkYcl
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。 n;%y
B: EXCEPT 运算符 6*sw,sU[y
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`DtiJ?$$0
C: INTERSECT 运算符 Y=9qJ`q
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。 IeZ&7u
注:使用运算词的几个查询结果行必须是一致的。 UIQQ\,3
12、说明:使用外连接 ~
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A、left outer join: HF]EU!OT
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。 p7s@%scp
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 tzPC/?
B:right outer join: h(_P9E[g
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。 \WcB9
C:full outer join:
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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。 4b]_
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二、提升 sA3UeTf
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) k'g$2
法一:select * into b from a where 1<>1 p<q].^M
法二:select top 0 * into b from a c&
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2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) <8f(eP\*F
insert into b(a, b, c) select d,e,f from b; u %'y_C3
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) U7E
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 o_sQQF
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. .?B{GnB>
4、说明:子查询(表名1:a 表名2:b) l^ARW
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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) \9'!"-i
5、说明:显示文章、提交人和最后回复时间 6p#g0t
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b I'dj.
6、说明:外连接查询(表名1:a 表名2:b) cs
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select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c W+.{4K
7、说明:在线视图查询(表名1:a ) inZi3@h)T
select * from (SELECT a,b,c FROM a) T where t.a > 1; jM]d'E?ZLA
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 \2j|=S6
select * from table1 where time between time1 and time2 wrabyRjK
select a,b,c, from table1 where a not between 数值1 and 数值2 ka#K
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9、说明:in 的使用方法 *o!l/>4g
select * from table1 where a [not] in ('值1','值2','值4','值6') @7fm1b
10、说明:两张关联表,删除主表中已经在副表中没有的信息 :\mRtVH
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) k}HQq_Y(<
11、说明:四表联查问题: vu<#wW*9
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 ..... _|X7
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12、说明:日程安排提前五分钟提醒 zi
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SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ;Xyte
13、说明:一条sql 语句搞定数据库分页 BB63xEx
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 Z2#`}GI_m
14、说明:前10条记录 l0Y?v 4
select top 10 * form table1 where 范围 9qr UM`z$g
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.) Z^*NnL.'
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) )yrAov\z*
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 q4k.f_{
(select a from tableA ) except (select a from tableB) except (select a from tableC) {c@G$
17、说明:随机取出10条数据 @UO}W_0ZD
select top 10 * from tablename order by newid() \-c#jo.$8
18、说明:随机选择记录 :@/"abv
select newid() e=7W7^"_
19、说明:删除重复记录 &+G;R
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) 'y.JcS!|
20、说明:列出数据库里所有的表名 ~p\n&{P0
select name from sysobjects where type='U' rGQ5l1</
21、说明:列出表里的所有的 @; ;G88=
select name from syscolumns where id=object_id('TableName') )&,K94
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 .TJ">?
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type [zQWyDu
显示结果: E M Q4yK
type vender pcs ;%Q&hwj
电脑 A 1 x,\!DLq:p
电脑 A 1 4sIXO
光盘 B 2 G mA!Mo
光盘 A 2 i4<BDX5
手机 B 3 *T1~)z}j<
手机 C 3 y(}Eko4u5
23、说明:初始化表table1 @\jQoaLT$_
TRUNCATE TABLE table1 _=EZ `!%
24、说明:选择从10到15的记录 h>klTPM>
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc @VK6JjIq
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三、技巧 . :a<2sp6
1、1=1,1=2的使用,在SQL语句组合时用的较多 TBnvV 5_
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ;&
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如: DW|vMpU]u
if @strWhere !='' kiX%3(
begin 2+:'0Krc
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ,{8v4b-
end OKAkl
else #wjH4DT
begin YE\K<T
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set @strSQL = 'select count(*) as Total from [' + @tblName + ']' '$[Di'*;
end `Mk4sKU\a
我们可以直接写成 qfrNi1\9-
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere [!~}S
2、收缩数据库 q@ZlJ3%l,
--重建索引 |')-VhLLK
DBCC REINDEX NXI[q'y
DBCC INDEXDEFRAG hcyO97@r
--收缩数据和日志 .S7:;%qL6
DBCC SHRINKDB
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DBCC SHRINKFILE m$:&P|!'p
3、压缩数据库 kjE*9bUc
dbcc shrinkdatabase(dbname) Q["t eo]DQ
4、转移数据库给新用户以已存在用户权限 Fw"$A0
exec sp_change_users_login 'update_one','newname','oldname' ~5 >[`)
go 3sbK7,4
5、检查备份集 6I>^Pf'ND
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' j?-R]^-5
6、修复数据库 _a5(s2wq+
ALTER DATABASE [dvbbs] SET SINGLE_USER ,2,5Odrz
GO d~Mg
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DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK i_ QcC
GO BJ5}GX!
ALTER DATABASE [dvbbs] SET MULTI_USER JJnYOau
GO jg_n 7
7、日志清除 E\$C/}T
SET NOCOUNT ON S_\
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DECLARE @LogicalFileName sysname, &z@~B&O
@MaxMinutes INT, nIBFk?)6
@NewSize INT h}&b+1{X
USE tablename -- 要操作的数据库名 ]tY:,Mfs
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 Cv^`&\[SW+
@MaxMinutes = 10, -- Limit on time allowed to wrap log. ;`UecLb#
@NewSize = 1 -- 你想设定的日志文件的大小(M) Yb:pAzw6
-- Setup / initialize :(p)1=I
DECLARE @OriginalSize int Lgi[u"Du
SELECT @OriginalSize = size _~M^ uW^l
FROM sysfiles kg>>D
WHERE name = @LogicalFileName JE;+T[I
SELECT 'Original Size of ' + db_name() + ' LOG is ' + %e_"CS
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + Qf@iU%G
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' f$F*3
FROM sysfiles "HlgRp]u
WHERE name = @LogicalFileName Ns=AjhLc z
CREATE TABLE DummyTrans ZnfNQl[
(DummyColumn char (8000) not null) +iA=y=;blH
DECLARE @Counter INT, NXU`wnVJ
@StartTime DATETIME, ; Lql_1
@TruncLog VARCHAR(255) *e/K:k
SELECT @StartTime = GETDATE(), 1%`7.;!i
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' BX< dSK
DBCC SHRINKFILE (@LogicalFileName, @NewSize) AGq>=avv
EXEC (@TruncLog) ]KuMz p!
-- Wrap the log if necessary. ]'h; {;ug
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired J/ W{/E>;
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) RU&_j*U
AND (@OriginalSize * 8 /1024) > @NewSize Bs!4H2@{(]
BEGIN -- Outer loop. FxRXPt
FK
SELECT @Counter = 0 "A[ b
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WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) |d}MxS`^
BEGIN -- update UtJ a3ya
INSERT DummyTrans VALUES ('Fill Log') `78V%\
DELETE DummyTrans AK-}V4C/A
SELECT @Counter = @Counter + 1 O#_b7i
END 50~K,Jx6B
EXEC (@TruncLog) ^gYD*K!*
END CxF-Z7 '
SELECT 'Final Size of ' + db_name() + ' LOG is ' + &`!^Zq vG
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + aGoE,5
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' [j9E pi(
FROM sysfiles 0KvVw rWJ
WHERE name = @LogicalFileName 51xk>_Hm}|
DROP TABLE DummyTrans #T3h}=
SET NOCOUNT OFF :&w{\-0{
8、说明:更改某个表 jbte
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exec sp_changeobjectowner 'tablename','dbo' Q+$Tt7/
9、存储更改全部表 +j[oE I`e
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch Z|*!y]We
@OldOwner as NVARCHAR(128), Ph,-sR
@NewOwner as NVARCHAR(128) cQUC.TZ_
AS ,)fkr]`<
DECLARE @Name as NVARCHAR(128) \2kPq>hu
DECLARE @Owner as NVARCHAR(128) ^g>1U5c
DECLARE @OwnerName as NVARCHAR(128) x\@*60o
DECLARE curObject CURSOR FOR z@VP:au
select 'Name' = name, r\M9_s8
'Owner' = user_name(uid) N "Wqy
from sysobjects Hs(D/&6%
where user_name(uid)=@OldOwner w4:\N U
order by name =f 7r69I"
OPEN curObject - u3e5gW
FETCH NEXT FROM curObject INTO @Name, @Owner }!d;(/)rb
WHILE(@@FETCH_STATUS=0) |qN'P}L
BEGIN >-)h|w i
if @Owner=@OldOwner ma& To=
begin "Ty/k8?
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ,FQK;BU!lh
exec sp_changeobjectowner @OwnerName, @NewOwner NAr1[{^E,
end _GoVx=t
-- select @name,@NewOwner,@OldOwner KL?) akk
FETCH NEXT FROM curObject INTO @Name, @Owner H+C6[W=
END L;6.r3bL
close curObject #AViM_u
deallocate curObject xN0*8
GO V H^AcO
10、SQL SERVER中直接循环写入数据 &KC!*}<tx
declare @i int XcfKx@l
set @i=1 z2yJ#
while @i<30 =zg:aTMti
begin X% {'<baR
insert into test (userid) values(@i) 2+"r~#K*
set @i=@i+1 JXU2CyMY
end /^7iZ|>:M:
小记存储过程中经常用到的本周,本月,本年函数 jE/oA<^
Dateadd(wk,datediff(wk,0,getdate()),-1) f [o%hCS
Dateadd(wk,datediff(wk,0,getdate()),6) *r,b=8|
Dateadd(mm,datediff(mm,0,getdate()),0) \fLvw
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) wts:65~
Dateadd(yy,datediff(yy,0,getdate()),0) O8u3y
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) ~H /2R
上面的SQL代码只是一个时间段 \h{r;#g
Dateadd(wk,datediff(wk,0,getdate()),-1) |M~ON=
Dateadd(wk,datediff(wk,0,getdate()),6) saZ>?Owz
就是表示本周时间段. >_ \<E!j
下面的SQL的条件部分,就是查询时间段在本周范围内的: v."Dnl
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 9.+/~$Ht
而在存储过程中 >^_ bD
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) `,Vv["^ PB
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) -_^c6!i