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。 V xN!Ki=
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一、基础 C4E* q3[Y
1、说明:创建数据库 D[T\_3W
CREATE DATABASE database-name aeMj4|{\
2、说明:删除数据库 E:}s6l
drop database dbname Njo.-k
3、说明:备份sql server j+.E#:tu"
--- 创建 备份数据的 device uToi4]w"y
USE master _bh$
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EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' >>=zkPy
--- 开始 备份 25G~rklk
BACKUP DATABASE pubs TO testBack VU\G49
4、说明:创建新表 B4OFhtYE
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) }T%E;m-
根据已有的表创建新表: 1%@i4
A:create table tab_new like tab_old (使用旧表创建新表) _576Qa'rm
B:create table tab_new as select col1,col2... from tab_old definition only h6Vd<sV\tf
5、说明:删除新表 a;i}<n7
drop table tabname tm;\m!^X{
6、说明:增加一个列 pJ?y
Alter table tabname add column col type V\Lh(zPt
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。 7WV"Wrl]
7、说明:添加主键: Alter table tabname add primary key(col) %i&am=
说明:删除主键: Alter table tabname drop primary key(col) sVO|Ghy65
8、说明:创建索引:create [unique] index idxname on tabname(col....) +MS*YpPW
删除索引:drop index idxname fN`Prs A
注:索引是不可更改的,想更改必须删除重新建。 -6q7ze{@
9、说明:创建视图:create view viewname as select statement ~HctXe' x
删除视图:drop view viewname 8pmWw?
10、说明:几个简单的基本的sql语句 D<Z\6)|%I
选择:select * from table1 where 范围 K/&
插入:insert into table1(field1,field2) values(value1,value2) Y(JZP\Tf_N
删除:delete from table1 where 范围 #;2kN
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更新:update table1 set field1=value1 where 范围 <Rt0
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查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! ziAn9/sT
排序:select * from table1 order by field1,field2 [desc] .j!:Hp(z}
总数:select count as totalcount from table1 2V @ pt
求和:select sum(field1) as sumvalue from table1 @C'qbO{
平均:select avg(field1) as avgvalue from table1 nCldH|>5w
最大:select max(field1) as maxvalue from table1 RZvRV?<bR
最小:select min(field1) as minvalue from table1 uL-$^],
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11、说明:几个高级查询运算词 *@
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A: UNION 运算符 >wV2` 6
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 O|;|7fCB\
B: EXCEPT 运算符 kKQD$g.z6
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。 J@Nq
C: INTERSECT 运算符 K>+c2;t;
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。 "jq F
注:使用运算词的几个查询结果行必须是一致的。 &>@EfW](
12、说明:使用外连接 m]++
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A、left outer join: Xp^71A?>
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。 btf]~YN
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 9@(V!G
B:right outer join: l%cE o`U
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。 yV@~B;eW0
C:full outer join: xqVIw!J?/}
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。 U,9=&"e b
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二、提升 Yv;iduc('
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 6r5<uZ9w_X
法一:select * into b from a where 1<>1 &-.2P!t
法二:select top 0 * into b from a uY)|
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) g<4@5OQKu
insert into b(a, b, c) select d,e,f from b; %?`$#*f\%
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) i;<H^\%
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 |A
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例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. mVyF M -`
4、说明:子查询(表名1:a 表名2:b) ^^*dHWHn<
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) M[dJQ(
5、说明:显示文章、提交人和最后回复时间 (d5kD#.N
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b fH
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6、说明:外连接查询(表名1:a 表名2:b) s4\_%je<v
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c "Kn%|\YL@4
7、说明:在线视图查询(表名1:a ) 9r,7>#IF
select * from (SELECT a,b,c FROM a) T where t.a > 1; oGZ%w4T
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 lGN{1djT
select * from table1 where time between time1 and time2 i\k>2df
select a,b,c, from table1 where a not between 数值1 and 数值2 )6-!,D0 db
9、说明:in 的使用方法 }W"/h)q
select * from table1 where a [not] in ('值1','值2','值4','值6') ]OA8H[U-eA
10、说明:两张关联表,删除主表中已经在副表中没有的信息 [RUYH5>Ik
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) uHO>FM,
11、说明:四表联查问题: &p^8zE s
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 ..... .\ces2,
12、说明:日程安排提前五分钟提醒 @X>Oj .
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 jUX0sRDk
13、说明:一条sql 语句搞定数据库分页 ^&8xfI6?
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 w`K=J!5y2g
14、说明:前10条记录 [Gb8o'
select top 10 * form table1 where 范围 r`CsR0[
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.) ^5*9BwH`
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) |Xk>a7X
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
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(select a from tableA ) except (select a from tableB) except (select a from tableC) @ * *]o
17、说明:随机取出10条数据 L Z#SX5N
select top 10 * from tablename order by newid() 2~*.X^dR
18、说明:随机选择记录 ;l=ZW
select newid() _0e;&2')
19、说明:删除重复记录 w+3-j
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) NXDuO_#
20、说明:列出数据库里所有的表名 zH+a*R
select name from sysobjects where type='U' 3 At%TA:
21、说明:列出表里的所有的 },G5!3
select name from syscolumns where id=object_id('TableName') gflu!C6
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。 rXu^]CK
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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 .~dNzonq
显示结果: ;JQ;LbEn
type vender pcs qm=N@@R&
电脑 A 1 EAXbbcV
电脑 A 1 1$ C\`
光盘 B 2 \B~}s }
光盘 A 2 ?T <2Cl'C
手机 B 3 u IGeSd5B
手机 C 3 dBMr%6tz
23、说明:初始化表table1 =6:>C9
TRUNCATE TABLE table1 J PK(S~
24、说明:选择从10到15的记录 DF!*S{)
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 0_faJjTbP;
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三、技巧 vCS D1~V_
1、1=1,1=2的使用,在SQL语句组合时用的较多 o79EDPX
"where 1=1" 是表示选择全部 "where 1=2"全部不选, hV]]%zwR+
如: -9z!fCu3
if @strWhere !='' yJAz#~PO/
begin /KH,11)yc
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere s xp>9&
end U0X? ~ 1
else 9s'[p'[Z
begin fC$(l@O?
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ijR,% qg
end aaODj>
我们可以直接写成 V1Opp8
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere )Cfk/OnRd
2、收缩数据库 TmIw?#q^
--重建索引 :N
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DBCC REINDEX `suEN@^
DBCC INDEXDEFRAG $,9A?'
--收缩数据和日志 &;]KntxB
DBCC SHRINKDB R-V4Ju[:
DBCC SHRINKFILE Doj>Irj?7
3、压缩数据库 nL@(|nJ[
dbcc shrinkdatabase(dbname) j!<(`
4、转移数据库给新用户以已存在用户权限 J}'a|a@bk
exec sp_change_users_login 'update_one','newname','oldname' rsgTd\b
go 8\/$cP"<^
5、检查备份集 $(8CU$gi=
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' I=G-(L/&
6、修复数据库 . +
ALTER DATABASE [dvbbs] SET SINGLE_USER <@z!kl
GO HXp$\%A)
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK E\Et,l#|LY
GO (6#,
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ALTER DATABASE [dvbbs] SET MULTI_USER 6wY6*R
GO yz7X7mAo
7、日志清除 yhSbX4Q
SET NOCOUNT ON \&Zp/;n
DECLARE @LogicalFileName sysname, jZ\a:K?
@MaxMinutes INT, T>2_ r6;
@NewSize INT `8sC>)lrwu
USE tablename -- 要操作的数据库名 kI|7o>}<
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 /pS Y ~*
@MaxMinutes = 10, -- Limit on time allowed to wrap log. +#V.6i
@NewSize = 1 -- 你想设定的日志文件的大小(M) r?j2%M\
-- Setup / initialize &<RK=e'*x
DECLARE @OriginalSize int r(VznKSx
SELECT @OriginalSize = size .ZK^kcyA
FROM sysfiles /\0g)B;]
WHERE name = @LogicalFileName }lP'bu
SELECT 'Original Size of ' + db_name() + ' LOG is ' + he\ pW5p
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 82*nC!P3E
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' o3OtG#g2
FROM sysfiles 9O2??N7f
WHERE name = @LogicalFileName _aj,tz
CREATE TABLE DummyTrans $4ZjN N@
(DummyColumn char (8000) not null) e"O c
DECLARE @Counter INT, ]]^eIjg>a6
@StartTime DATETIME, 6k-
@TruncLog VARCHAR(255) l1I\khS
SELECT @StartTime = GETDATE(), bc}BQ|Q
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 2Mo oqJp
DBCC SHRINKFILE (@LogicalFileName, @NewSize) {usv*Cm
EXEC (@TruncLog) \\UOpl
-- Wrap the log if necessary. =dM'n}@U
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired &b:SDl6
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) :qe.*\
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AND (@OriginalSize * 8 /1024) > @NewSize s i=m5$V
BEGIN -- Outer loop. z<u*I@;
SELECT @Counter = 0 ;xxu ,
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) D(&XmC[\Y
BEGIN -- update rctGa ,l
INSERT DummyTrans VALUES ('Fill Log') _my!YS5n
DELETE DummyTrans .Gq]Mrim9G
SELECT @Counter = @Counter + 1 ews{0
END A$o7<Hx
EXEC (@TruncLog) =jIP29+
END eOU v#F
SELECT 'Final Size of ' + db_name() + ' LOG is ' + (29BS(|!
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 6[~_;0
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' fIwG9cR
FROM sysfiles fx3oA}
WHERE name = @LogicalFileName 3 =-XA2zJ
DROP TABLE DummyTrans * ,#SwZ
SET NOCOUNT OFF {&,MkWgG
8、说明:更改某个表 M>_
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exec sp_changeobjectowner 'tablename','dbo' Lh
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9、存储更改全部表 rMEM$1vPU
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch @b{I0+li"/
@OldOwner as NVARCHAR(128), 3K{G =WE$
@NewOwner as NVARCHAR(128) 6s(.ul
AS "p\5:<
DECLARE @Name as NVARCHAR(128) tx_h1[qi
DECLARE @Owner as NVARCHAR(128) h=
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DECLARE @OwnerName as NVARCHAR(128) C=,O'U(ep
DECLARE curObject CURSOR FOR m[8?d~
select 'Name' = name, oj%(@6L
'Owner' = user_name(uid) (F=q/lK$
from sysobjects *pj^d><
where user_name(uid)=@OldOwner :xy4JRcF
order by name i!u:]14>
OPEN curObject mGP&NOR0^y
FETCH NEXT FROM curObject INTO @Name, @Owner >\4"k4d}
WHILE(@@FETCH_STATUS=0) wGhy"1g#
BEGIN EaN1xb(DYa
if @Owner=@OldOwner ag{cm'.
begin Ce`#J6lT
set @OwnerName = @OldOwner + '.' + rtrim(@Name) #Pr
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exec sp_changeobjectowner @OwnerName, @NewOwner V<ExR@|}.%
end Gk-49|qIV
-- select @name,@NewOwner,@OldOwner y)uxj-G
FETCH NEXT FROM curObject INTO @Name, @Owner hA:RVeS{
END D7|qFx;]g
close curObject 2qpUUo f
deallocate curObject =" ;G&)H-
GO 2`P=ekF]
10、SQL SERVER中直接循环写入数据 mZ0'-ax
declare @i int Q nmv?YXS
set @i=1 `RHhc{
while @i<30 ESi'3mbeC
begin /Xf_b.ZM&
insert into test (userid) values(@i) B
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set @i=@i+1 W!B\VB
end MN<uIqG
小记存储过程中经常用到的本周,本月,本年函数 Yc p<N>)
Dateadd(wk,datediff(wk,0,getdate()),-1) LVe[N-K
Dateadd(wk,datediff(wk,0,getdate()),6) JxmFUheLt
Dateadd(mm,datediff(mm,0,getdate()),0) "(+p1
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) |] cFsB#G
Dateadd(yy,datediff(yy,0,getdate()),0) lOEB ,/P
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) }UX0 eI4
上面的SQL代码只是一个时间段 |f{(MMlj
Dateadd(wk,datediff(wk,0,getdate()),-1) u{8:VX
Dateadd(wk,datediff(wk,0,getdate()),6) Bv{DZ?{s
就是表示本周时间段. =.(~`ici~
下面的SQL的条件部分,就是查询时间段在本周范围内的: ;Q\MH t*
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 6Ij'z9nJw
而在存储过程中 AR3v,eOs
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) w42=tN+B
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) wq:"/2p1