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。 ",Cr,;]
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一、基础 YY5!_k
1、说明:创建数据库 y~
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CREATE DATABASE database-name `T&jPA9eY
2、说明:删除数据库 %)(Cp-b!
drop database dbname 3n;K!L%zMT
3、说明:备份sql server $8~e}8dt|
--- 创建 备份数据的 device v]VWDT
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USE master 1iBP,:>*
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' }}
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--- 开始 备份 rS8 w\`_
BACKUP DATABASE pubs TO testBack Hi}RZMr1
4、说明:创建新表 $E!J:Y=
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) j\&pej
根据已有的表创建新表: ~d
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A:create table tab_new like tab_old (使用旧表创建新表) v&
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B:create table tab_new as select col1,col2... from tab_old definition only * ?Jz2[B
5、说明:删除新表 r@G#[.*A>
drop table tabname WyhhCR=;
6、说明:增加一个列 f 2YLk
Alter table tabname add column col type b Bc- ^
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。 c1XX~8
7、说明:添加主键: Alter table tabname add primary key(col) f!_
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说明:删除主键: Alter table tabname drop primary key(col) 5*-3?
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8、说明:创建索引:create [unique] index idxname on tabname(col....) 7^6uG6
删除索引:drop index idxname K9Hqq7"%
注:索引是不可更改的,想更改必须删除重新建。 fS&6
9、说明:创建视图:create view viewname as select statement X[yNFW}S2W
删除视图:drop view viewname 6<76H
10、说明:几个简单的基本的sql语句 ~NcQ1.
选择:select * from table1 where 范围 @.C{OSHE
插入:insert into table1(field1,field2) values(value1,value2) BMyzjteS+
删除:delete from table1 where 范围 S.*~C0"
更新:update table1 set field1=value1 where 范围 <%?#AVU[
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! o4y']JSN
排序:select * from table1 order by field1,field2 [desc] p
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总数:select count as totalcount from table1 eD?3"!c!
求和:select sum(field1) as sumvalue from table1 @OpNHQat9
平均:select avg(field1) as avgvalue from table1 dt\jGD
最大:select max(field1) as maxvalue from table1 rf&M!d}!
最小:select min(field1) as minvalue from table1 %3r:s`{
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11、说明:几个高级查询运算词 07v!Zj
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A: UNION 运算符 7V7zGx+Z7
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。 5s{j=.O
B: EXCEPT 运算符 ;]2s,za)qs
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。 Y"g.IK`V
C: INTERSECT 运算符 ,F6=b/eZ
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。 pc]J[ S?P
注:使用运算词的几个查询结果行必须是一致的。 sBX-X$*N
12、说明:使用外连接 ^Q<mV*~
A、left outer join: ]b?9zeT*'l
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。 @C_KV0i
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 Ta=s:trP
B:right outer join: @@G6p($
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。 -e GL) M
C:full outer join: Q
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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。 $tqJ/:I
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二、提升 ]y{WD=T
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) nuQ]8- ,
法一:select * into b from a where 1<>1 NE2pL@sk
法二:select top 0 * into b from a pmvT$;7I
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) bBcp9C)iY
insert into b(a, b, c) select d,e,f from b; &C<yfRDu
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) !%(h2]MQ
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 /UcV
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. iSLGwTdLn
4、说明:子查询(表名1:a 表名2:b) zw<p74DH
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) yM.IxpT#$
5、说明:显示文章、提交人和最后回复时间 CK+d!Eg
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b K kW;-{c
6、说明:外连接查询(表名1:a 表名2:b) {=2DqkTD
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 2NGeC0=
7、说明:在线视图查询(表名1:a ) E_z;s3AXQ
select * from (SELECT a,b,c FROM a) T where t.a > 1; uQ$^;Pr
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 #65^w=Sp}
select * from table1 where time between time1 and time2 {@Yb%{+
select a,b,c, from table1 where a not between 数值1 and 数值2 8LkP)]4^sO
9、说明:in 的使用方法 IA zZ1#/3
select * from table1 where a [not] in ('值1','值2','值4','值6') W<ZK,kv
10、说明:两张关联表,删除主表中已经在副表中没有的信息 `$LWmm#
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) :e1o<JgPt
11、说明:四表联查问题: ~5
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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 ..... aVs(EHF
12、说明:日程安排提前五分钟提醒 ( lm&*tKm
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 +ECDD'^!
13、说明:一条sql 语句搞定数据库分页 _Q%vK*n
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 ]
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14、说明:前10条记录 g:l.MJT
select top 10 * form table1 where 范围 g1E~+@
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.) *.-.iY.a]
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) 1F8 W9b^D
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 1F'1>Bu~
(select a from tableA ) except (select a from tableB) except (select a from tableC) WO5O?jo'
17、说明:随机取出10条数据 8M,9kXq{L
select top 10 * from tablename order by newid() _ZB\L^j)
18、说明:随机选择记录 2aZw[7s
select newid() %_-zWVJ
19、说明:删除重复记录 mMx ;yZ
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) !rDdd%Z
20、说明:列出数据库里所有的表名 w.\w1:d
select name from sysobjects where type='U' [S]S^ej*8
21、说明:列出表里的所有的 O`GsS{$sS
select name from syscolumns where id=object_id('TableName') dCe4u<so\
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 `nXVE+E@
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type MTER(L
显示结果: 7\zZpPDV
type vender pcs
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电脑 A 1 \6?A!w~6
电脑 A 1 3ya1'qUC
光盘 B 2 5RH2"*8T
光盘 A 2 k#Of]mXXz
手机 B 3 ,Y?sfp
手机 C 3 =\#%j|9N9
23、说明:初始化表table1 X=JmF97
TRUNCATE TABLE table1 GDhE[of
24、说明:选择从10到15的记录 0_P}z3(M
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc kd:$oS_*s
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三、技巧 aJL^AG
1、1=1,1=2的使用,在SQL语句组合时用的较多 OJN2z
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 5
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如: w@-PqsF
if @strWhere !='' X:a`B(@S
begin a {}|Bf<
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere G&xo1K]
end hv 6@Jr3
else iqQUtE]E_
begin s5.AW8X=?*
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' (iJ1
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end <e]Oa$
我们可以直接写成 q+KzIde|%
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 1aVa0q<
2、收缩数据库 :WI.LKlo~
--重建索引 .x`M<L#M(
DBCC REINDEX \;-fi.Hrf$
DBCC INDEXDEFRAG XoLJ L]+?
--收缩数据和日志 6$a$K,dZ
DBCC SHRINKDB b `2|I {
DBCC SHRINKFILE ;4M><OS!
3、压缩数据库 9=w|)p )
dbcc shrinkdatabase(dbname) 9odJr]
4、转移数据库给新用户以已存在用户权限 {8,<ZZ_
exec sp_change_users_login 'update_one','newname','oldname' 5(W"-A}
go J89Dul l
5、检查备份集 n?\ nn3
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' Mypc3
6、修复数据库 \T]EZ'+O
ALTER DATABASE [dvbbs] SET SINGLE_USER ,P'P^0qJ
GO L@75-T
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK G$'jEa<:u
GO y-p70.'{U
ALTER DATABASE [dvbbs] SET MULTI_USER x\&`>>uA
GO ^_5L"F]sP
7、日志清除 ihh4pD27g
SET NOCOUNT ON Q9d`zR]
DECLARE @LogicalFileName sysname, ;!91^Tl
@MaxMinutes INT, k4qp u=@U
@NewSize INT GU't%[
USE tablename -- 要操作的数据库名 jztq.2-c#
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 4L-:*b_v\
@MaxMinutes = 10, -- Limit on time allowed to wrap log. <R%;~) {
@NewSize = 1 -- 你想设定的日志文件的大小(M) 6Ao%>;e*
-- Setup / initialize BQcE9~H
DECLARE @OriginalSize int ;U1UFqZ`
SELECT @OriginalSize = size 6{[pou&
FROM sysfiles a $"ib
WHERE name = @LogicalFileName !3mA0-!+
SELECT 'Original Size of ' + db_name() + ' LOG is ' + p~ C.IG
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + VL[R(a6c
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CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' Y+4o B
FROM sysfiles O\K_q7iO6
WHERE name = @LogicalFileName
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CREATE TABLE DummyTrans N=:5eAza
(DummyColumn char (8000) not null) 0JgL2ayIVI
DECLARE @Counter INT, `28};B>
@StartTime DATETIME, VIP7OHJh
@TruncLog VARCHAR(255) *Ype>x{
SELECT @StartTime = GETDATE(), nf1#tlIJd
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' >FhK#*Pa
DBCC SHRINKFILE (@LogicalFileName, @NewSize) )
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EXEC (@TruncLog) i>EgG5iJ
-- Wrap the log if necessary. d=,%=@
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired ;})5:\h
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 7'wS\/e4a
AND (@OriginalSize * 8 /1024) > @NewSize Qr1e@ =B
BEGIN -- Outer loop. L,d
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SELECT @Counter = 0 S$f6a'
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) Q^p|Ldj
BEGIN -- update bX.ja;;
INSERT DummyTrans VALUES ('Fill Log') @i^~0A#q*
DELETE DummyTrans DC1'Kyk
SELECT @Counter = @Counter + 1 =0@&GOq
END ?JV|dM
EXEC (@TruncLog) 6"c1;P!4
END s5RjIa0$7
SELECT 'Final Size of ' + db_name() + ' LOG is ' + v+jsC`m
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + KXV[OF&J
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' IHgeQ F
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FROM sysfiles f84:hXo6
WHERE name = @LogicalFileName h'
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DROP TABLE DummyTrans l5+gsEux]
SET NOCOUNT OFF ZEYgK)^
8、说明:更改某个表 |F.)zC5{
exec sp_changeobjectowner 'tablename','dbo' {]z4k[;.h
9、存储更改全部表 o!:8nXw
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch
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@OldOwner as NVARCHAR(128), e]=!"nJ+
@NewOwner as NVARCHAR(128) 1!pa;$L
AS r>jC_7
DECLARE @Name as NVARCHAR(128) }HE6aF62O
DECLARE @Owner as NVARCHAR(128) )BfT7{WN
DECLARE @OwnerName as NVARCHAR(128)
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DECLARE curObject CURSOR FOR Soie^$
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select 'Name' = name, Mv c`)_Md
'Owner' = user_name(uid) +0),xu
from sysobjects ;['[?wk
where user_name(uid)=@OldOwner d:G]1k;z
order by name P}.7Mehf
OPEN curObject AxxJk"v'y
FETCH NEXT FROM curObject INTO @Name, @Owner m/N dJMoN=
WHILE(@@FETCH_STATUS=0) 3] 1-M
BEGIN nhG
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if @Owner=@OldOwner FWH}j0Gj|
begin j3q~E[Mz\
set @OwnerName = @OldOwner + '.' + rtrim(@Name) mDh1>>K'~
exec sp_changeobjectowner @OwnerName, @NewOwner rF\"w0J_
end R),zl_d_
-- select @name,@NewOwner,@OldOwner .1 %T
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FETCH NEXT FROM curObject INTO @Name, @Owner pT?Q#,fh
END yL;M"L
close curObject c9R5w.t:
deallocate curObject M MzGd:0b
GO w&4~Q4
10、SQL SERVER中直接循环写入数据 -@>BHC
declare @i int nW"q
set @i=1 ~[k%oA%W
while @i<30 ,G#.BLH
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begin *5<Sr q'
insert into test (userid) values(@i) 1 nvTce
set @i=@i+1 cI]WrI2CQa
end Q-#$Aa
小记存储过程中经常用到的本周,本月,本年函数 l{w#H|]
Dateadd(wk,datediff(wk,0,getdate()),-1) <8UYhGK
Dateadd(wk,datediff(wk,0,getdate()),6) fF*`'i=!
Dateadd(mm,datediff(mm,0,getdate()),0) =h(W4scgqX
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) &R~n>>c
Dateadd(yy,datediff(yy,0,getdate()),0) VL'
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Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) iqnJ~g
上面的SQL代码只是一个时间段 T]Nu)
Dateadd(wk,datediff(wk,0,getdate()),-1) %!ebO*8q
Dateadd(wk,datediff(wk,0,getdate()),6) b|SE<\
就是表示本周时间段. K
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下面的SQL的条件部分,就是查询时间段在本周范围内的: VL[)[~^
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) gPC*b+
而在存储过程中 'WHHc 9rG,
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) `>DP,D)w(
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) g+-;J+X8