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。 < gB>j\:
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一、基础 L9nv05B
1、说明:创建数据库 *c4uCI:0t
CREATE DATABASE database-name H_KE^1
2、说明:删除数据库 ?nJ7lLQA
drop database dbname {$z )7s
3、说明:备份sql server T`KH7y|bv
--- 创建 备份数据的 device ;> **+ezF
USE master yep`~``_
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ,g2|8>sJP
--- 开始 备份 ]Aap4+s
BACKUP DATABASE pubs TO testBack $~vy,^
4、说明:创建新表 "@U9'rKx
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) <6^MVaD
根据已有的表创建新表: s2A3.SN
A:create table tab_new like tab_old (使用旧表创建新表) Bf!i(gM
B:create table tab_new as select col1,col2... from tab_old definition only 6,
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5、说明:删除新表 \~!9T5/*
drop table tabname E6a$c`H@?
6、说明:增加一个列 @Aa$k:_
Alter table tabname add column col type g.OBh_j-v
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 :acnrW>i[@
7、说明:添加主键: Alter table tabname add primary key(col) n B4)%
说明:删除主键: Alter table tabname drop primary key(col) OrP-+eg
8、说明:创建索引:create [unique] index idxname on tabname(col....) {o"X8
删除索引:drop index idxname 54~`8f
注:索引是不可更改的,想更改必须删除重新建。 hNBv|&D#
9、说明:创建视图:create view viewname as select statement z3+y|nx!
删除视图:drop view viewname nM:e<`r
10、说明:几个简单的基本的sql语句 TP'
选择:select * from table1 where 范围 wHm{4
插入:insert into table1(field1,field2) values(value1,value2) "&?F6Pi
删除:delete from table1 where 范围 >B(%$jG Z
更新:update table1 set field1=value1 where 范围 7[5g_D t
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! L4`bGZl55
排序:select * from table1 order by field1,field2 [desc] *KNj5>6=
总数:select count as totalcount from table1 f!hQ"1[
求和:select sum(field1) as sumvalue from table1 K=Z~$)Og)
平均:select avg(field1) as avgvalue from table1 ~qQSt%
最大:select max(field1) as maxvalue from table1 ,73kh
最小:select min(field1) as minvalue from table1 z`UL)W
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11、说明:几个高级查询运算词 ixF
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A: UNION 运算符 q<(yNqMKP
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。 K6<@DP+/
B: EXCEPT 运算符 &!>
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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。 .),ql_sXr
C: INTERSECT 运算符 {~NiGHY
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。 bM7y}P5`1
注:使用运算词的几个查询结果行必须是一致的。 ol]"r5#Q_H
12、说明:使用外连接 JJ@O5
A、left outer join: OZ 4uk.)
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。 ,]HH%/h
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 =" Q5Z6W
B:right outer join: lM
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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。 /V@~Vlww
C:full outer join: >DX\^86x
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。 ,b;eU[!]
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二、提升 $1<V'b[E
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) Zp'c>ty=
法一:select * into b from a where 1<>1 4oW6&1
法二:select top 0 * into b from a mFCDwh]
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) eytd@-7uX
insert into b(a, b, c) select d,e,f from b; A0{ !m
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) vg@kPuOiO
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件
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例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. Q/[|/uNw?
4、说明:子查询(表名1:a 表名2:b) ;/gH6Z?
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) s}Y_og_c
5、说明:显示文章、提交人和最后回复时间 .)Xyzd
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b ["l1\YCi
6、说明:外连接查询(表名1:a 表名2:b) yt,xA;g
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c N"-</kzV
7、说明:在线视图查询(表名1:a ) S[!sJ-rG
select * from (SELECT a,b,c FROM a) T where t.a > 1; .xJW=G{/
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 AITV+=sN
select * from table1 where time between time1 and time2 72rnMHq
select a,b,c, from table1 where a not between 数值1 and 数值2 &k'J5YHm8H
9、说明:in 的使用方法 eu!B
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select * from table1 where a [not] in ('值1','值2','值4','值6') nNuv 0
10、说明:两张关联表,删除主表中已经在副表中没有的信息 E/x2LYH
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) e}|UVoeH
11、说明:四表联查问题: uJ:'<dJ
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 ..... OsS5WY0H
12、说明:日程安排提前五分钟提醒 EOqvu=$6
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 76e%&ZG)Q
13、说明:一条sql 语句搞定数据库分页 aD
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select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 1rs`|iX5
14、说明:前10条记录 U)IW6)q
select top 10 * form table1 where 范围 ?-"xP'#
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) /8V#6d_
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) E]zTd$v6
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 32DT]{-N!
(select a from tableA ) except (select a from tableB) except (select a from tableC) Y@)iPK@z
17、说明:随机取出10条数据 );4lM%]eb
select top 10 * from tablename order by newid() q ld2<W
18、说明:随机选择记录 z}I4m
select newid() w!$|IC
19、说明:删除重复记录 H.\gLIr
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) py9zDWk~
20、说明:列出数据库里所有的表名 \
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select name from sysobjects where type='U' 8Ar5^.k
21、说明:列出表里的所有的 AvW2)+6G
select name from syscolumns where id=object_id('TableName') oU }eAZj{
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 +eiM6* /0
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type nC Mv&{~
显示结果: 'FB?#C %U
type vender pcs 2-G he3
电脑 A 1 EdQ:8h
电脑 A 1 {d`e9^Z:
光盘 B 2 =-#>NlB$w
光盘 A 2 dP8b\H
手机 B 3 /cn=8%!N
手机 C 3 L_f u<W
23、说明:初始化表table1 XA8{N
TRUNCATE TABLE table1 aA Hx^X^
24、说明:选择从10到15的记录 >Mml+4<5
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc H{*~d+:ol
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三、技巧 \x JGR!
1、1=1,1=2的使用,在SQL语句组合时用的较多 bzFwQi}>
"where 1=1" 是表示选择全部 "where 1=2"全部不选, :r0?[#r?N,
如: Q+e|;Mj
if @strWhere !='' W5a)`%H
begin "#uXpCuw
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere |Sg
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end 2{!o"6t
else )4oTA@wR
begin S{cy|QD
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' x!CCSM;q
end /15e-(Zz/
我们可以直接写成 }S{#DgZ@X
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere CRy;>UI
2、收缩数据库 cx?XJ)
--重建索引 B%HG7
DBCC REINDEX X}?`G?'
DBCC INDEXDEFRAG n[Jpy[4g
--收缩数据和日志 UEeD Nl$^u
DBCC SHRINKDB ur\v[k=
DBCC SHRINKFILE STMc@MeZU_
3、压缩数据库 BU|=`Kb|))
dbcc shrinkdatabase(dbname) NUVFG;
4、转移数据库给新用户以已存在用户权限 DgOO\
exec sp_change_users_login 'update_one','newname','oldname' Gi})*U]P|
go DyiyH%SSD
5、检查备份集 o"F=3b~:n
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' <ptZY.8N
6、修复数据库 _97A9wHj
ALTER DATABASE [dvbbs] SET SINGLE_USER $bQ[H[4l
GO hr9[$4'H
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK +o]DT7W
GO 8^26g3
ALTER DATABASE [dvbbs] SET MULTI_USER h^E"eC
GO 2y6 e]D
7、日志清除 @ToY,@]e
SET NOCOUNT ON V4]t=3>
DECLARE @LogicalFileName sysname, 5 rpX"(
@MaxMinutes INT, $[5S M>e]
@NewSize INT +{
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USE tablename -- 要操作的数据库名 &S/@i|_
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 QXTl'.SfF
@MaxMinutes = 10, -- Limit on time allowed to wrap log. }Gmwm|`*
@NewSize = 1 -- 你想设定的日志文件的大小(M) nH*JR
-- Setup / initialize 2H7b2%
DECLARE @OriginalSize int R
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SELECT @OriginalSize = size K.k%Tg[ ~
FROM sysfiles &jJj6
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WHERE name = @LogicalFileName }GV5':W@WG
SELECT 'Original Size of ' + db_name() + ' LOG is ' + CmyCne
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + B%Pg:|
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' zQt"i`{U
FROM sysfiles T 8.
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WHERE name = @LogicalFileName q
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CREATE TABLE DummyTrans 0c,)T1NG >
(DummyColumn char (8000) not null) - /
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DECLARE @Counter INT, Z'V"nhL
@StartTime DATETIME, 1%^d<%,]
@TruncLog VARCHAR(255) br[n5
SELECT @StartTime = GETDATE(), zNo(|;19
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ?04$1n:
DBCC SHRINKFILE (@LogicalFileName, @NewSize) R3<2Z0lqy
EXEC (@TruncLog) -:jC.}
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-- Wrap the log if necessary. 7XDze(O5
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired D$vP&7pOr4
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) f:K3 P[|
AND (@OriginalSize * 8 /1024) > @NewSize o<f#Zi
BEGIN -- Outer loop. qbunP!
SELECT @Counter = 0 gT=RJB
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) nWzGb2Y
BEGIN -- update @9}SHS
INSERT DummyTrans VALUES ('Fill Log') J_tI]?jrU
DELETE DummyTrans mz<wYV*
SELECT @Counter = @Counter + 1 Q|1X|_hs
END ->0OqVQA
EXEC (@TruncLog) AY~~ a)V
END #ozQF~
SELECT 'Final Size of ' + db_name() + ' LOG is ' + Cjn)`Q8
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 1(ud(8?|
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' WER\04%D\m
FROM sysfiles LqOjVQxz
WHERE name = @LogicalFileName OQC.p,SO
DROP TABLE DummyTrans Z7@~#)3
SET NOCOUNT OFF /EXubU73
8、说明:更改某个表 :
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exec sp_changeobjectowner 'tablename','dbo' ==W`qC4n?n
9、存储更改全部表 \NN5'DBx
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch uJX(s6["=
@OldOwner as NVARCHAR(128), rQ!X
@NewOwner as NVARCHAR(128) VdfV5"
AS ZR|cZH1}C
DECLARE @Name as NVARCHAR(128) 7lJs{$
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DECLARE @Owner as NVARCHAR(128) 3~uWrZ.u
DECLARE @OwnerName as NVARCHAR(128) SyWLPh
DECLARE curObject CURSOR FOR zV<vwIUrr
select 'Name' = name, 5uJ{#Zd
'Owner' = user_name(uid) ?4&C)[^
from sysobjects e52y}'L
where user_name(uid)=@OldOwner *?Pbk+}%
order by name h+!
OPEN curObject /t<C_lLM
FETCH NEXT FROM curObject INTO @Name, @Owner `=B0NC.3
WHILE(@@FETCH_STATUS=0) nP+]WUnY
BEGIN aRh1Q=^@(4
if @Owner=@OldOwner (H*d">`mz
begin g\n0v~T+
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ^^{gn3xJ
exec sp_changeobjectowner @OwnerName, @NewOwner DwLl}{r'
end RlH~<|XK
-- select @name,@NewOwner,@OldOwner mI[$c"!BD
FETCH NEXT FROM curObject INTO @Name, @Owner ~1`ZPLVG
END yN Bb(!u
close curObject OlV'#D
deallocate curObject Wxxnc#;lv
GO ?R;K`f9<
10、SQL SERVER中直接循环写入数据 =`oQcIkz
declare @i int \EC=#E(
set @i=1 D#~S<>u@
while @i<30 "V:24\vO
begin 4GY:N6qe'
insert into test (userid) values(@i) M]Y72K^
set @i=@i+1 w<uK-]t
end xTJ-v/t3<
小记存储过程中经常用到的本周,本月,本年函数 $2M dxw5
Dateadd(wk,datediff(wk,0,getdate()),-1) 2[*r9%W
Dateadd(wk,datediff(wk,0,getdate()),6) q hPvU(
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Dateadd(mm,datediff(mm,0,getdate()),0) l9 |x7GB
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) DB^"iof
Dateadd(yy,datediff(yy,0,getdate()),0) x*9CK8o=
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 2|1s !Q
上面的SQL代码只是一个时间段
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Dateadd(wk,datediff(wk,0,getdate()),-1) y,*>+xk,
Dateadd(wk,datediff(wk,0,getdate()),6) LE|*Je3a
就是表示本周时间段. wlh V!a0>
下面的SQL的条件部分,就是查询时间段在本周范围内的: .o2]ndT/J
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ]vPa
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而在存储过程中 ?`nF"u>
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) CFW\
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 9 pGND]tIi