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。 .5|AX6p+^
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一、基础 oQI3Yz
1、说明:创建数据库 sguE{!BO
CREATE DATABASE database-name +b1(sk=4z
2、说明:删除数据库 xcwyn\93)
drop database dbname K/79Tb-
3、说明:备份sql server (h7 rW3
--- 创建 备份数据的 device 1i4KZ"A5+
USE master 0vNEl3f'O
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' KL,=Z&.<=
--- 开始 备份 'm}K$h(U
BACKUP DATABASE pubs TO testBack ZW }*]rg
4、说明:创建新表 y _M<\b
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ]24aK_Uu
根据已有的表创建新表: zM"OateA
A:create table tab_new like tab_old (使用旧表创建新表) VI0^Zq!6R
B:create table tab_new as select col1,col2... from tab_old definition only f!a[+^RB:
5、说明:删除新表 )+RTA
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drop table tabname D oX!P|*
6、说明:增加一个列 &0SX*KyI
Alter table tabname add column col type A#M#JI-Y
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 dX{|-;6vm
7、说明:添加主键: Alter table tabname add primary key(col) N~_GJw@
说明:删除主键: Alter table tabname drop primary key(col) &!]$#
8、说明:创建索引:create [unique] index idxname on tabname(col....) ^qs=fF
删除索引:drop index idxname )a.Y$![
注:索引是不可更改的,想更改必须删除重新建。 m619bzFlB
9、说明:创建视图:create view viewname as select statement jhrmQS
删除视图:drop view viewname 4YM!S E-I
10、说明:几个简单的基本的sql语句 W_9-JM(r
选择:select * from table1 where 范围 vt<r_&+ pJ
插入:insert into table1(field1,field2) values(value1,value2) W,5A|Q~
删除:delete from table1 where 范围 U(3+*'8r,1
更新:update table1 set field1=value1 where 范围 /+pbO-r W*
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! I>o+INb:
排序:select * from table1 order by field1,field2 [desc] dawe!w!
总数:select count as totalcount from table1 vpcx 1t<
求和:select sum(field1) as sumvalue from table1 rM#jxAb
平均:select avg(field1) as avgvalue from table1 K@Q_q/(%;
最大:select max(field1) as maxvalue from table1
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最小:select min(field1) as minvalue from table1 Iq0_X7:{QI
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11、说明:几个高级查询运算词 35B G&;C
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A: UNION 运算符 r/'9@oM
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 cP%mkh_ri
B: EXCEPT 运算符 Kj,C9
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 h!ZEZ|{
C: INTERSECT 运算符 EGL1[7It`
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 ojU:RRr4l$
注:使用运算词的几个查询结果行必须是一致的。 ~Z!!wDHS
12、说明:使用外连接 E</UmM+ R
A、left outer join: (m80isl
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。 |>@Gbgw^M
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 CwZ+Pn0
B:right outer join: 2%U)y;$m2
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。
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C:full outer join: $7eO33Bm
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 i71,
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二、提升 p s=jGh[
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) =G3O7\KmH
法一:select * into b from a where 1<>1 Yh)yp?
法二:select top 0 * into b from a Wm$(b2t
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) N|K,{
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insert into b(a, b, c) select d,e,f from b; Q1J./C}
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) =8O057y
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 #Ki(9oWd
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. x=Z\c,@O
4、说明:子查询(表名1:a 表名2:b) n_\VG[f
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) U<{8nMB
5、说明:显示文章、提交人和最后回复时间 ?nJ7lLQA
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b .|
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6、说明:外连接查询(表名1:a 表名2:b) BTjfzfO"
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c <
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7、说明:在线视图查询(表名1:a ) }ozlED`E
select * from (SELECT a,b,c FROM a) T where t.a > 1; ;> **+ezF
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
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select * from table1 where time between time1 and time2 H6(kxpOI\
select a,b,c, from table1 where a not between 数值1 and 数值2 oVutHt
9、说明:in 的使用方法 gXN#<g,:^
select * from table1 where a [not] in ('值1','值2','值4','值6') ]Aap4+s
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;$)Oz
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) >y)(M(o
11、说明:四表联查问题: Ug02G
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 ..... e\x=4i
12、说明:日程安排提前五分钟提醒 <6^MVaD
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 Ry>c]\a]
13、说明:一条sql 语句搞定数据库分页 .4Ob?ZS(
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 >ch{u{i6
14、说明:前10条记录 v9R#=m/=
select top 10 * form table1 where 范围 BqC, -gC
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.) <ABN/nH
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) RB<LZHZI
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 }YJ(|z""
(select a from tableA ) except (select a from tableB) except (select a from tableC) 3"=% [
17、说明:随机取出10条数据 0jCYOl
select top 10 * from tablename order by newid() ^{&Vv(~!Q
18、说明:随机选择记录 H?98^y7
select newid() Xr\|U89P
19、说明:删除重复记录 1;cV [&3
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) le*mr0a
20、说明:列出数据库里所有的表名 uU(G &:@
select name from sysobjects where type='U' 6OR5zXpk
21、说明:列出表里的所有的 S6-)N(3|
select name from syscolumns where id=object_id('TableName') @k:f(c
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。 9z7^0Ruw
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 %^s;{aN*!
显示结果: aiVd^(
type vender pcs q<`YJ,
电脑 A 1 TxAT ))
电脑 A 1 &os9K)
光盘 B 2 92_F8y*D
光盘 A 2 S|!)_RL
手机 B 3 H&jK|]UXoO
手机 C 3 Sx)b~ *
23、说明:初始化表table1 $3>k/*=
TRUNCATE TABLE table1 DpjiE/*
24、说明:选择从10到15的记录 }[ LME Z
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ,73kh
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三、技巧 D QO~<E6c
1、1=1,1=2的使用,在SQL语句组合时用的较多 )W9W8>Cc5_
"where 1=1" 是表示选择全部 "where 1=2"全部不选, z}\TS.
如: -q1vB8gjj
if @strWhere !='' 2RXU75VY
begin KdU!wsKfG
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere QA?e2kd
end ^@?-YWt
else (|%YyRaX
begin rlG&wX
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ol]"r5#Q_H
end JJ@O5
我们可以直接写成 gwE#,OY*
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere S <~"\<ED
2、收缩数据库 SrGX4
--重建索引 lZoy(kdc
DBCC REINDEX x+Vp&
DBCC INDEXDEFRAG mU.(aLHW
--收缩数据和日志 cU
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DBCC SHRINKDB ?K,xxH
DBCC SHRINKFILE >7%Gd-;l
3、压缩数据库 UjLZ!-}
dbcc shrinkdatabase(dbname) h+EG)
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4、转移数据库给新用户以已存在用户权限 .ko8`J%%M
exec sp_change_users_login 'update_one','newname','oldname' {2wfv2hQ
go eytd@-7uX
5、检查备份集 Hq9yu*!u
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' RC(fhqV
6、修复数据库 9pAklD 4
ALTER DATABASE [dvbbs] SET SINGLE_USER A[20ic
GO / J 3
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK W rvSYqN
GO Vk%[N>
ALTER DATABASE [dvbbs] SET MULTI_USER }{"a}zOl
GO Brw-"tmx
7、日志清除 |eS5~0<`
SET NOCOUNT ON v:otR%yt
DECLARE @LogicalFileName sysname, >q+o
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@MaxMinutes INT, 5 :O7c Br
@NewSize INT ^Mw>'*5^
USE tablename -- 要操作的数据库名 JMp>)*YS
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 bvyX(^I[q
@MaxMinutes = 10, -- Limit on time allowed to wrap log. r9!jIkILz
@NewSize = 1 -- 你想设定的日志文件的大小(M) Z"spua5
-- Setup / initialize MExP'9
DECLARE @OriginalSize int Z^t" !oY
SELECT @OriginalSize = size a/d'(]
FROM sysfiles .hI3Uv8[
WHERE name = @LogicalFileName s$g"6;_\
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 8yr_A[S8.
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + Y{c_5YYf
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' ~!o\uTVr
FROM sysfiles :e9}k5kdk
WHERE name = @LogicalFileName n_G< /8
CREATE TABLE DummyTrans }T<[JXh=J
(DummyColumn char (8000) not null) /?<tjK' "H
DECLARE @Counter INT, q,b6).
@StartTime DATETIME, "Mt4~vy
@TruncLog VARCHAR(255) Wi a%rm
SELECT @StartTime = GETDATE(), =4RXNWkud
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' py9zDWk~
DBCC SHRINKFILE (@LogicalFileName, @NewSize) \
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EXEC (@TruncLog) ?6h65GO{
-- Wrap the log if necessary. rn1^6qy)
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired B> kx$_~
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) Y02 cX@K6
AND (@OriginalSize * 8 /1024) > @NewSize <~:Lp:6 J
BEGIN -- Outer loop. bZ!*s
SELECT @Counter = 0 <~9z.v7
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000))
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BEGIN -- update N?!]^jI,
INSERT DummyTrans VALUES ('Fill Log') rUC@Bf
DELETE DummyTrans YGy.39@31
SELECT @Counter = @Counter + 1 Nh7Dz
END 7CfHL;+m<4
EXEC (@TruncLog) S{cy|QD
END c(@V
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + vby[#S|
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + %E q}H
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' c"X` OB
FROM sysfiles ^l\U6$3
WHERE name = @LogicalFileName &WW|! 6
DROP TABLE DummyTrans I;dc[m
SET NOCOUNT OFF )bc0 t]Fs
8、说明:更改某个表 H]@M00C
exec sp_changeobjectowner 'tablename','dbo' [}s nKogp
9、存储更改全部表 kh3PEq
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch _tE`W96J
@OldOwner as NVARCHAR(128), PprCz"
@NewOwner as NVARCHAR(128) <"I#lib
AS N}0-L$@SL
DECLARE @Name as NVARCHAR(128) V:?exJg9
DECLARE @Owner as NVARCHAR(128) s;-(dQ{O
DECLARE @OwnerName as NVARCHAR(128) `TNWLD@Z
DECLARE curObject CURSOR FOR Y{P0?`
select 'Name' = name, TxZ ^zj
'Owner' = user_name(uid) NUVFG;
from sysobjects P$E #C:=
where user_name(uid)=@OldOwner `Q d_Gu,M
order by name a4gJ-FE
OPEN curObject _~ m@ SI
FETCH NEXT FROM curObject INTO @Name, @Owner `TvpKS5.Y
WHILE(@@FETCH_STATUS=0) R
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BEGIN <uXZ*E
if @Owner=@OldOwner w4YuijhW
begin Z1j3 F
set @OwnerName = @OldOwner + '.' + rtrim(@Name) @d imZsi1
exec sp_changeobjectowner @OwnerName, @NewOwner .
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end | /,XdTSy
-- select @name,@NewOwner,@OldOwner T%kr&XsQX
FETCH NEXT FROM curObject INTO @Name, @Owner 5[Sa7Mk
END Ew>E]Ys
close curObject E"p;
deallocate curObject \v(}@zcB|
GO XW]'by
10、SQL SERVER中直接循环写入数据 $RxS<_tj
declare @i int &6-udZB-
set @i=1 @ i$jyc
while @i<30 ;eYm+e^?.
begin 29R_?HBH
insert into test (userid) values(@i) V gLnpPOQ
set @i=@i+1 92|\`\LP%
end }G,PUjg_^3
小记存储过程中经常用到的本周,本月,本年函数 sJ{S(wpi"
Dateadd(wk,datediff(wk,0,getdate()),-1) <d".v
Dateadd(wk,datediff(wk,0,getdate()),6) 3 ZO\Pu
Dateadd(mm,datediff(mm,0,getdate()),0) `Pa z
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) j2A
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Dateadd(yy,datediff(yy,0,getdate()),0) %3B0s?,I
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) #l kv&.)x
上面的SQL代码只是一个时间段 IbFS8 *a\
Dateadd(wk,datediff(wk,0,getdate()),-1) ZzZy2.7
Dateadd(wk,datediff(wk,0,getdate()),6) yu ~Rk
就是表示本周时间段. dtHB@\1
下面的SQL的条件部分,就是查询时间段在本周范围内的: IKT3T_\-I
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) K0hmRR=
而在存储过程中 rr/0pa$
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ?7Kl)p3
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) I"TFj$Pg