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。 h6n!"z8H
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一、基础 y=Z[_L!xr
1、说明:创建数据库 &WOm[]Q4
CREATE DATABASE database-name +\?+cXSc
2、说明:删除数据库 RxNLn/?d@
drop database dbname YL78cWOs
3、说明:备份sql server &3 Ki
--- 创建 备份数据的 device <{@ D^L6h
USE master \U##b~Z,g
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' h
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--- 开始 备份 _>;{+XRX[
BACKUP DATABASE pubs TO testBack XVb9)a
4、说明:创建新表 L-9;"]d~|
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) i0*Cs#(=h
根据已有的表创建新表: T Qx<lw
A:create table tab_new like tab_old (使用旧表创建新表) 57O|e/2
B:create table tab_new as select col1,col2... from tab_old definition only IZ87Px>zL
5、说明:删除新表 wQ[!~>A
drop table tabname ]2YC7
6、说明:增加一个列 fRq+pUxU
Alter table tabname add column col type 0A-yQzL|
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。 #lMC#Ld
7、说明:添加主键: Alter table tabname add primary key(col) pF9WKpzE
说明:删除主键: Alter table tabname drop primary key(col) u:tcL-;U
8、说明:创建索引:create [unique] index idxname on tabname(col....) ei"c|/pO
删除索引:drop index idxname [j0jAl
注:索引是不可更改的,想更改必须删除重新建。 J8ScKMUN2
9、说明:创建视图:create view viewname as select statement %oquHkX%OJ
删除视图:drop view viewname %UhLCyC/
10、说明:几个简单的基本的sql语句 sx]{N
选择:select * from table1 where 范围 Qvel#*-4
插入:insert into table1(field1,field2) values(value1,value2) J3e'?3w[
删除:delete from table1 where 范围 kD7'BP/#
更新:update table1 set field1=value1 where 范围 _18Z]XtX
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 5NhAb$q2Y
排序:select * from table1 order by field1,field2 [desc] H9(UzyN>i
总数:select count as totalcount from table1 W39J)~D^@
求和:select sum(field1) as sumvalue from table1 6q!Q([D_
平均:select avg(field1) as avgvalue from table1 o6:bmKWE
最大:select max(field1) as maxvalue from table1 GG-b)64h`
最小:select min(field1) as minvalue from table1 [:qJ1^U U
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11、说明:几个高级查询运算词 }RKsS3}
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A: UNION 运算符 OW@"j;6
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UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 :$gs7<z{rm
B: EXCEPT 运算符 atw*t1)g
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。 jeJspch+#
C: INTERSECT 运算符 _8-T?j**
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。 O(v>\MV
注:使用运算词的几个查询结果行必须是一致的。 B9$pG
12、说明:使用外连接 :UAcS^n7h"
A、left outer join: ^f-)gZ&
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 vK+!m~kDu
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c .o,-a >jL
B:right outer join: 2v;&`04V<
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 Bj9FSKiH
C:full outer join: _HjB'XNr(
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 lQ4^I^?m
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二、提升 H q?F @X
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) t0kZFU
法一:select * into b from a where 1<>1 Fy!s$!\C0
法二:select top 0 * into b from a ^:mKTiA-
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) %M/L/_d
insert into b(a, b, c) select d,e,f from b; <|]i3_Z
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) U2tgBF?)A
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 r`.Bj0
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. P}( c0/
4、说明:子查询(表名1:a 表名2:b) a=x&sz\x
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) F9d6#~
5、说明:显示文章、提交人和最后回复时间 "%S-(ue:
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b VUP.
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6、说明:外连接查询(表名1:a 表名2:b) VS_\bIC
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c q?)5yukeF
7、说明:在线视图查询(表名1:a ) [O|c3;
select * from (SELECT a,b,c FROM a) T where t.a > 1; Qh6vH9(D
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 j9GKz1
select * from table1 where time between time1 and time2 e'c3.sQ|?
select a,b,c, from table1 where a not between 数值1 and 数值2 7y42)X
9、说明:in 的使用方法 o?~27
select * from table1 where a [not] in ('值1','值2','值4','值6') .F2"tt?'
10、说明:两张关联表,删除主表中已经在副表中没有的信息 L{l}G,j<
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) cKOXsdH?SL
11、说明:四表联查问题: ~l.C-
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 ..... 59v=\; UI
12、说明:日程安排提前五分钟提醒 Vpzjh,r-j
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 Y C<FKWc
13、说明:一条sql 语句搞定数据库分页 xj&~>&U){;
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 6c27X/'Z
14、说明:前10条记录 2PUB@B'
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select top 10 * form table1 where 范围 [;4ak)!
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.) I9rQX9#B
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) Z#[%JUYp'
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 ygX!'evY
(select a from tableA ) except (select a from tableB) except (select a from tableC) mA_EvzXk\
17、说明:随机取出10条数据 ;-l^X%r
select top 10 * from tablename order by newid() |nr;OM
18、说明:随机选择记录 }H
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select newid() RBg2iG$8|
19、说明:删除重复记录 4>H0a
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) U3v~R4
20、说明:列出数据库里所有的表名 X56q,jCJ{
select name from sysobjects where type='U' *f{4_ts
21、说明:列出表里的所有的 ,KF>@3f
select name from syscolumns where id=object_id('TableName') 6 OvH"/X4
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。 zlTLp-^Y
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 SB5qm?pT8<
显示结果: zQt)>Qx_
type vender pcs !{ _:k%B
电脑 A 1 AW9%E/{
电脑 A 1 DT6BFx
光盘 B 2 rM6S%rS
光盘 A 2 +u t%C.1
手机 B 3 pU,\ &3N
手机 C 3 !=yO72dgLY
23、说明:初始化表table1 T nyLVIP
TRUNCATE TABLE table1 dVGcth;
24、说明:选择从10到15的记录 Z=%u:K}[
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc '%:E4oI
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三、技巧 PJe\PGh
1、1=1,1=2的使用,在SQL语句组合时用的较多 m7XN6zX
"where 1=1" 是表示选择全部 "where 1=2"全部不选, %u<r_^w5
如: K;s`
if @strWhere !='' v<g#/X8
begin wN6sica|
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere W~i0.rg|>
end eecIF0hp
else vl|3WYA
begin z~v-8aw
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' k<f0moxs'
end F8{T/YhZ
我们可以直接写成 @T.F/Pjhc
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere zJ ;]z0O
2、收缩数据库 |8x_Av0
--重建索引 i12G\Ye
DBCC REINDEX Et}%sdS
DBCC INDEXDEFRAG #.Ly
--收缩数据和日志 '=Jz}F <
DBCC SHRINKDB {4p7r7n'
DBCC SHRINKFILE $U. 2"
3、压缩数据库 dr(e)eD(R>
dbcc shrinkdatabase(dbname) 8
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4、转移数据库给新用户以已存在用户权限 I<xcVY9L
exec sp_change_users_login 'update_one','newname','oldname' 6O 2sa-{d
go 6Q+VW_~
5、检查备份集 !ueh%V Ky
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' A,=
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6、修复数据库 BP4vOZ0$
ALTER DATABASE [dvbbs] SET SINGLE_USER ?o/p}6
GO ilQ\+xR{b
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK Yx ;j
GO to#2.
ALTER DATABASE [dvbbs] SET MULTI_USER F0r5$Pl*
GO 09G]t1!,
7、日志清除
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SET NOCOUNT ON xcJvXp
DECLARE @LogicalFileName sysname, f)Z'#[A*t7
@MaxMinutes INT, I9U
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@NewSize INT B8upv~U6
USE tablename -- 要操作的数据库名 ?q5HAIZ`
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 JKCV>k
@MaxMinutes = 10, -- Limit on time allowed to wrap log. Vt9o8naz
@NewSize = 1 -- 你想设定的日志文件的大小(M) )coA30YR
-- Setup / initialize Th~pju
DECLARE @OriginalSize int (ueH@A"9;
SELECT @OriginalSize = size }JT&lyO< b
FROM sysfiles pBQ[lPCY/
WHERE name = @LogicalFileName *1>T c,mb
SELECT 'Original Size of ' + db_name() + ' LOG is ' + _F8-4
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + :b#5cMUe
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' ~n/:a
FROM sysfiles ~ r$I&8
WHERE name = @LogicalFileName _qQo}|/q
CREATE TABLE DummyTrans :n
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(DummyColumn char (8000) not null) u/\Ipk/
DECLARE @Counter INT, otP2qAI
@StartTime DATETIME, )S_%Ip
@TruncLog VARCHAR(255) )MX%DQw
SELECT @StartTime = GETDATE(), x}reeqn
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' Ja@?.gW
DBCC SHRINKFILE (@LogicalFileName, @NewSize) C|QJQ@bj0
EXEC (@TruncLog) :+ "JPF4X
-- Wrap the log if necessary. kYd=DY
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired rj5)b:c}
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) h 'is#X 6:
AND (@OriginalSize * 8 /1024) > @NewSize ^AUQsRA7PZ
BEGIN -- Outer loop. FOcDBCrOe
SELECT @Counter = 0 ab 6D &
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) Mq6_Q07
BEGIN -- update ];0:aSi#
INSERT DummyTrans VALUES ('Fill Log') EkN>5).
DELETE DummyTrans gJzS,g1]
SELECT @Counter = @Counter + 1 i\MW'b
END W*4!A\K
EXEC (@TruncLog) er !+QD,EM
END 7G_lGV_
SELECT 'Final Size of ' + db_name() + ' LOG is ' + `R$bx 64
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + {Z[kvXf"mZ
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ):Ekf2
FROM sysfiles RWn#"~
WHERE name = @LogicalFileName MpJx>0j/J
DROP TABLE DummyTrans [@s5v
SET NOCOUNT OFF bW'Y8ok[v
8、说明:更改某个表 6M8(KN^
exec sp_changeobjectowner 'tablename','dbo' r8L'C
9、存储更改全部表 B#4 J![BX
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch H329P*P
@OldOwner as NVARCHAR(128), yhyh\.
@NewOwner as NVARCHAR(128) )#Y:Bj7H@2
AS uRw%`J4H
DECLARE @Name as NVARCHAR(128) Fd9Z7C
DECLARE @Owner as NVARCHAR(128) 7|?Ht]
DECLARE @OwnerName as NVARCHAR(128) 6r,zOs-I]
DECLARE curObject CURSOR FOR 9p"';*{=
select 'Name' = name, m$q*
'Owner' = user_name(uid) u #7AB>wi{
from sysobjects @{8805Dp
where user_name(uid)=@OldOwner jbTyM"Y
order by name j !`2Z@
OPEN curObject zU};|Zw
FETCH NEXT FROM curObject INTO @Name, @Owner =iPQ\_ON@
WHILE(@@FETCH_STATUS=0) #kQLHi3##
BEGIN P99s
if @Owner=@OldOwner vYG$>*
begin 7jF2m'(
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 2?owXcbx
exec sp_changeobjectowner @OwnerName, @NewOwner oga0h'
end ]^l-k@
-- select @name,@NewOwner,@OldOwner Xc]Q_70O
FETCH NEXT FROM curObject INTO @Name, @Owner Qp>Q-+e0
END H0mDs7
close curObject O,KlZf_B
deallocate curObject =TXc- J
GO k8"[)lDc.
10、SQL SERVER中直接循环写入数据 vy F(k3W
declare @i int UIw6~a3E
set @i=1 eYRm:KC
while @i<30 YA^g[,
begin Z?'){\$*
insert into test (userid) values(@i) knZ<V%/e
set @i=@i+1 1uhSP!b
end i'vjvc~
小记存储过程中经常用到的本周,本月,本年函数 Q|cA8Fn
Dateadd(wk,datediff(wk,0,getdate()),-1) Ad`jV_z
Dateadd(wk,datediff(wk,0,getdate()),6) 1Aa=&B2
Dateadd(mm,datediff(mm,0,getdate()),0) 8f|+045E@
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) .DHRPel
Dateadd(yy,datediff(yy,0,getdate()),0) &Lgi
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) %|3UWN
上面的SQL代码只是一个时间段 Ehf{Kl
Dateadd(wk,datediff(wk,0,getdate()),-1) V?cUQghHg
Dateadd(wk,datediff(wk,0,getdate()),6) =p';y&
就是表示本周时间段. rhvsd2zi
下面的SQL的条件部分,就是查询时间段在本周范围内的: N
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Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) S>p>$m,
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而在存储过程中 DnPV
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select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) cj/FqU"
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) nyB~C7zR