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。 rk
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一、基础 ] ]XXcQ,A
1、说明:创建数据库 W:JR\KKU
CREATE DATABASE database-name o'K= X E
2、说明:删除数据库 ([dJ'OPx$
drop database dbname G>,43S!<
3、说明:备份sql server gubw&W
--- 创建 备份数据的 device @ )Nw>/;o
USE master `wKd##v'@
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' (Rh$0^)A
--- 开始 备份 2hsRYh
BACKUP DATABASE pubs TO testBack uSUog+i
4、说明:创建新表 C2H2*"
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) W#kd[Wi
根据已有的表创建新表: @]7s`?
A:create table tab_new like tab_old (使用旧表创建新表) $g_|U:,
B:create table tab_new as select col1,col2... from tab_old definition only .S*VYt%K7
5、说明:删除新表 <FfmDR
drop table tabname 0( q:K6zI}
6、说明:增加一个列 )3.=)?XW
Alter table tabname add column col type [xo-ZDIoG
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 WOi+y
7、说明:添加主键: Alter table tabname add primary key(col) DdqE6qE
说明:删除主键: Alter table tabname drop primary key(col) 17#t 7Yk
8、说明:创建索引:create [unique] index idxname on tabname(col....) VI]~uTV
删除索引:drop index idxname ~rlPS#]o
注:索引是不可更改的,想更改必须删除重新建。 c!N#nt_<
9、说明:创建视图:create view viewname as select statement 7n]ukqZ
删除视图:drop view viewname lofP$
10、说明:几个简单的基本的sql语句 S/dj])g
选择:select * from table1 where 范围 yM('!iG*/
插入:insert into table1(field1,field2) values(value1,value2) GD%qrK?
删除:delete from table1 where 范围 {9vMc
更新:update table1 set field1=value1 where 范围 BAojP1}+,
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! ;:/C.%d
排序:select * from table1 order by field1,field2 [desc] zMh`Uqid
总数:select count as totalcount from table1 Rk#p zD
求和:select sum(field1) as sumvalue from table1 QL:Qzr[
平均:select avg(field1) as avgvalue from table1 %OOy90b2
最大:select max(field1) as maxvalue from table1
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最小:select min(field1) as minvalue from table1 P"+R:O\!g
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11、说明:几个高级查询运算词 <[vsGUbc
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A: UNION 运算符 (t5vBUj
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。 EQ]>^VE2B
B: EXCEPT 运算符 j\iNag(
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。 ySHpN>U
C: INTERSECT 运算符 ^O<@I
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。 Y>x3`f]
注:使用运算词的几个查询结果行必须是一致的。 a]!u
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12、说明:使用外连接 .|@2Uf
A、left outer join: duc\/S'
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。 Q-J} :U
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 Q5]rc`}
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B:right outer join: m[ER~]L/C
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。 BmaY&?
C:full outer join: hPuF:iiQ4
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。 a:KL{e[
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二、提升 b^A7R{G7
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 2 SU
法一:select * into b from a where 1<>1 Bf;<3k)5.
法二:select top 0 * into b from a A@Cvx7X
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 8S5Q{[ !
insert into b(a, b, c) select d,e,f from b;
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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) k ~4o`eA
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 E {UhM q7
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) 2 ,krVb?<
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) ?*6Q;.f<
5、说明:显示文章、提交人和最后回复时间 ni6zo~+W]
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b }(oWXwFb&W
6、说明:外连接查询(表名1:a 表名2:b) xeKm} MN]S
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ,YRBYK:
7、说明:在线视图查询(表名1:a ) #Q BW%L
select * from (SELECT a,b,c FROM a) T where t.a > 1; JsEnhE}]
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 WR_B:%W.
select * from table1 where time between time1 and time2 4#W*f3d[@:
select a,b,c, from table1 where a not between 数值1 and 数值2 L s+zJ1
9、说明:in 的使用方法 yq!peFu
select * from table1 where a [not] in ('值1','值2','值4','值6') Y=,9 M
10、说明:两张关联表,删除主表中已经在副表中没有的信息 Gn4XVzB`O
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) b>]UNf"-
11、说明:四表联查问题: tMXNi\Bj
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 ..... 4{G>T
12、说明:日程安排提前五分钟提醒 GC|V>| tz#
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 iFZ.a.NDc
13、说明:一条sql 语句搞定数据库分页 Ym6v 4k!@O
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 _Td#C1g3
14、说明:前10条记录 pcQgWjfS
select top 10 * form table1 where 范围 ?Zb3M
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.) T8^l}Y
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select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ErFt5%FN.O
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 {kvxz
(select a from tableA ) except (select a from tableB) except (select a from tableC) } ?MbU6"
17、说明:随机取出10条数据 +BE_t(%p"
select top 10 * from tablename order by newid() n4.\}%=z
18、说明:随机选择记录 k%iwt]i%
select newid() "whs?^/
19、说明:删除重复记录 fcy4?SQ.<i
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) /N,\ st
20、说明:列出数据库里所有的表名 [fY7|
select name from sysobjects where type='U' k1SD{BL
21、说明:列出表里的所有的 ?)Je%H
select name from syscolumns where id=object_id('TableName') 7>F [7_
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。 .3#Xjhebvu
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 `aA)n;{/2u
显示结果: "~KTLf
type vender pcs >_$_fB
电脑 A 1 [zSt+K;
电脑 A 1 [;UI8Stw
光盘 B 2 uMRzUK`QK
光盘 A 2 yCkX+{ki
手机 B 3 SiJ{
手机 C 3 bfYVA2=Z
23、说明:初始化表table1 Eo6qC?5<
TRUNCATE TABLE table1 8idI Jm%y
24、说明:选择从10到15的记录 @LSX@V
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc u|k_OUTq
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三、技巧 G<]@nP{P
1、1=1,1=2的使用,在SQL语句组合时用的较多 f8G<5_!K_
"where 1=1" 是表示选择全部 "where 1=2"全部不选, -9Ygn_M
如: aj=-^iGG
if @strWhere !='' BkY#wJ'
begin ab#z&jg!
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere BB_(!omq[
end OX?E3 <8`
else L[<CEk
begin ^ >
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set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ^/#8 "
end h"'}Z^
我们可以直接写成 )1$H7|
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere JIqg[Mao
2、收缩数据库 K3h"oVn
--重建索引 y\[q2M<
DBCC REINDEX ?b93! Q1
DBCC INDEXDEFRAG nB]mj_)R^
--收缩数据和日志 b *3h}n;
DBCC SHRINKDB `wr*@/P
DBCC SHRINKFILE J|@D @\?7
3、压缩数据库 3o"l
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dbcc shrinkdatabase(dbname) +}Mm5^6*
4、转移数据库给新用户以已存在用户权限 ?.n1t@sG&
exec sp_change_users_login 'update_one','newname','oldname' \j &&o
go <GLoTolZ
5、检查备份集 BuUM~k&SY
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' T0.sL9
6、修复数据库 e E(+
ALTER DATABASE [dvbbs] SET SINGLE_USER 0QxBC7`qp
GO &}K%F)S
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK if3z Fh
GO }J2f$l>R
ALTER DATABASE [dvbbs] SET MULTI_USER q(4Ny<=,'K
GO .u`A4;;Gw
7、日志清除 {xOzxLB;
SET NOCOUNT ON }SyK)W5Y
DECLARE @LogicalFileName sysname, THB[(3q
@MaxMinutes INT, zU!d(ge.E
@NewSize INT 7!)VOD8Z
USE tablename -- 要操作的数据库名 PYzTKjw
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 cr?ZXu_
@MaxMinutes = 10, -- Limit on time allowed to wrap log. edZBQmx+#
@NewSize = 1 -- 你想设定的日志文件的大小(M) %(H'
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-- Setup / initialize ^NM>xIenf
DECLARE @OriginalSize int F+j"bhe
SELECT @OriginalSize = size B~J63Os/
FROM sysfiles @;KvUR/+FE
WHERE name = @LogicalFileName JbMp /
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 8Qj1%Ri:U
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 9[DlJ@T}
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' ePxAZg$ `>
FROM sysfiles *)oBE{6D
WHERE name = @LogicalFileName `B,R+==G:
CREATE TABLE DummyTrans sGpAaGY>
(DummyColumn char (8000) not null) fzAkUvo
DECLARE @Counter INT, G>jC+0nkry
@StartTime DATETIME, q'IMt7}
@TruncLog VARCHAR(255) JSaF7(a =
SELECT @StartTime = GETDATE(), r=p^~tuyxr
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' AJ3Byb=.
DBCC SHRINKFILE (@LogicalFileName, @NewSize) cIK4sOTJ&
EXEC (@TruncLog) _1WA:7$C
-- Wrap the log if necessary. .Yz^r?3t
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired +ZFN8
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) M&sQnPFH
AND (@OriginalSize * 8 /1024) > @NewSize NLUO{'uUW
BEGIN -- Outer loop. t**d{P+
SELECT @Counter = 0 m9]Ge]
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) Rm6i[y&
BEGIN -- update oZdY0n h4
INSERT DummyTrans VALUES ('Fill Log') (E~6fb"c
DELETE DummyTrans DJqJ6 z:'
SELECT @Counter = @Counter + 1 zsR5"Vi=
END =.JcIT'
EXEC (@TruncLog) dP>FXgY
END S@y?E}
SELECT 'Final Size of ' + db_name() + ' LOG is ' + hW6Ksn,*
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + uD[T l
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 09{ s'
FROM sysfiles a4Z e!l(
WHERE name = @LogicalFileName ULs'oT)K;
DROP TABLE DummyTrans ikb77?.
SET NOCOUNT OFF DG&aFmC
8、说明:更改某个表 a=v H:D
exec sp_changeobjectowner 'tablename','dbo' WGyPyG#Fl
9、存储更改全部表 Dd-a*6|x
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch L:Mjd47L
@OldOwner as NVARCHAR(128), -8dz`o}
@NewOwner as NVARCHAR(128) +rhBC
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AS K}GRU)
DECLARE @Name as NVARCHAR(128) K$r)^K=s
DECLARE @Owner as NVARCHAR(128) .YP&E1lNi
DECLARE @OwnerName as NVARCHAR(128) 73SH[f[g
DECLARE curObject CURSOR FOR !XM*y
select 'Name' = name, 1s(i\&B
'Owner' = user_name(uid) I7#JT?\}
from sysobjects d<WNN1f
where user_name(uid)=@OldOwner 2]FRIy
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order by name tCPK_Wws?Z
OPEN curObject "5?1S-Vl
FETCH NEXT FROM curObject INTO @Name, @Owner _j*I\
WHILE(@@FETCH_STATUS=0) fr$6&HDZ9
BEGIN ;vbMC74J#
if @Owner=@OldOwner ""_B3'
begin A5]yC\*zt
set @OwnerName = @OldOwner + '.' + rtrim(@Name) e<FMeg7n
exec sp_changeobjectowner @OwnerName, @NewOwner Z`zLrXPD)
end 4X+I2CD
-- select @name,@NewOwner,@OldOwner ]\k&
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FETCH NEXT FROM curObject INTO @Name, @Owner 7#7|+%W0
END rp2g./2
close curObject !\O!Du
deallocate curObject FJxb!-0&
GO 7KJ0>0~Et
10、SQL SERVER中直接循环写入数据 @2-;,VL3
declare @i int 9`? M-U
set @i=1 V'UFc>{o
while @i<30 8U4In[4
begin ~[~#PO
insert into test (userid) values(@i) Pv3G?u=4
set @i=@i+1 #\ysn|!J,
end @ `mke4>_
小记存储过程中经常用到的本周,本月,本年函数 e~cg
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Dateadd(wk,datediff(wk,0,getdate()),-1) |x>5 T}
Dateadd(wk,datediff(wk,0,getdate()),6) ,|,kU0xXz
Dateadd(mm,datediff(mm,0,getdate()),0) ^L8:..+:
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) */K]sQZa
Dateadd(yy,datediff(yy,0,getdate()),0) 2v#gCou
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) q:iu
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上面的SQL代码只是一个时间段 UnEgsfN
Dateadd(wk,datediff(wk,0,getdate()),-1) NzeiGj
Dateadd(wk,datediff(wk,0,getdate()),6) Y]uVA`%"b
就是表示本周时间段. 5r~hs6H
下面的SQL的条件部分,就是查询时间段在本周范围内的: v(Sh+p
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ]^i^L
而在存储过程中 ]9JH.fF
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) !$!%era`
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) iM6(bmc.