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。 nd]SI;<
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一、基础 2
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1、说明:创建数据库 6@s!J8!
CREATE DATABASE database-name f^FFn32u
2、说明:删除数据库 se\f be ^0
drop database dbname m,lZy#02s3
3、说明:备份sql server ^1najUpQ_n
--- 创建 备份数据的 device $DoR@2~y
USE master -N8rs[c
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' w}gmVJ#p
--- 开始 备份 `G qe]ZE#"
BACKUP DATABASE pubs TO testBack h+}BtKA
4、说明:创建新表 T&lgWOls
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) TI'v /=;)
根据已有的表创建新表: =vbG'_[7
A:create table tab_new like tab_old (使用旧表创建新表) 053bM)qW
B:create table tab_new as select col1,col2... from tab_old definition only QWk3y"5n<
5、说明:删除新表 YI g(^>sq
drop table tabname cD0rU8x
6、说明:增加一个列 XVqOiv)
Alter table tabname add column col type :~otzI4%!
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 LqbI/AQ)
7、说明:添加主键: Alter table tabname add primary key(col) 5MVa;m
说明:删除主键: Alter table tabname drop primary key(col) CIx(SeEF
8、说明:创建索引:create [unique] index idxname on tabname(col....) 3>KEl^1DB
删除索引:drop index idxname c_3B: F7
注:索引是不可更改的,想更改必须删除重新建。 iApq!u,
9、说明:创建视图:create view viewname as select statement &Q3Fgj
删除视图:drop view viewname ,AP0*Ln
10、说明:几个简单的基本的sql语句 GGp.u@\r
选择:select * from table1 where 范围 uzBQK
插入:insert into table1(field1,field2) values(value1,value2) w}ji]V}
删除:delete from table1 where 范围 t3@+idE b
更新:update table1 set field1=value1 where 范围 &BRk<iwV
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! L[x`i'0B
排序:select * from table1 order by field1,field2 [desc] /eI|m9ke
总数:select count as totalcount from table1 G&ck98
求和:select sum(field1) as sumvalue from table1 *%Rmdyn
平均:select avg(field1) as avgvalue from table1 P.y +jyu
最大:select max(field1) as maxvalue from table1 (xHmucmwp
最小:select min(field1) as minvalue from table1 J].Oxch&y
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11、说明:几个高级查询运算词 =Kd'(ct
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A: UNION 运算符 G?s9c0f
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 o;$xN3f,
B: EXCEPT 运算符 $G".PWc
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。 Q;]JVT1
C: INTERSECT 运算符 KqK]R6>
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。 F\m^slsu7=
注:使用运算词的几个查询结果行必须是一致的。 z`wIb
12、说明:使用外连接 6KMO*v
A、left outer join: ,<v0(
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。 .nPOjwEx&Y
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 JOJ.79CT
B:right outer join: XQo\27Fo
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。 Lc{AB!Br
C:full outer join: ANhqS
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。 aJ'Fn
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二、提升 cnu&!>8V
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) IL*B@E8
法一:select * into b from a where 1<>1 (/A.,8Ad
法二:select top 0 * into b from a y
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2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 731Lz*IFg
insert into b(a, b, c) select d,e,f from b; @7Ec(]yp
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) f/)Y {kS6
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 QP(0
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. y98FEG#S}
4、说明:子查询(表名1:a 表名2:b) (VeK7cU
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+ +Dk7B
5、说明:显示文章、提交人和最后回复时间 EtcT:k?y
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b q3x"9i
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6、说明:外连接查询(表名1:a 表名2:b) \u,CixV=
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c !D=!
7、说明:在线视图查询(表名1:a ) 8 0tA5AP
select * from (SELECT a,b,c FROM a) T where t.a > 1; 2FMmANH0ev
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 riIubX#
select * from table1 where time between time1 and time2 0~U#DTx0
select a,b,c, from table1 where a not between 数值1 and 数值2 Ui'v'
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9、说明:in 的使用方法 t]h_w7!U
select * from table1 where a [not] in ('值1','值2','值4','值6') #Zdh<.
10、说明:两张关联表,删除主表中已经在副表中没有的信息 o%_-u
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delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) /HdXJL9B
11、说明:四表联查问题: A(2 0+
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 ..... r8EJ@pOF2w
12、说明:日程安排提前五分钟提醒 ZFtx&vrP
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 4|?(LHBD)
13、说明:一条sql 语句搞定数据库分页 1aAOT6h
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 ~O}r<PQ
14、说明:前10条记录 [+\He/M6
select top 10 * form table1 where 范围 2j-l<!s
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.) A%^?z.
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ctP+ECH
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 Cog }a
(select a from tableA ) except (select a from tableB) except (select a from tableC) p/{%%30ke
17、说明:随机取出10条数据 In?rQiD9
select top 10 * from tablename order by newid() ^T&{ORWz
18、说明:随机选择记录 hk?i0#7W
select newid() HZ9 >4G3
19、说明:删除重复记录 {y"Kn'1
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) JLd%rM\m
20、说明:列出数据库里所有的表名 nE]rPRU}[
select name from sysobjects where type='U' ;P S4@,
21、说明:列出表里的所有的 ;>PHkJQ
select name from syscolumns where id=object_id('TableName') sPNm.W$_
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。 1UMEbb
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 Bl+\|[yd
显示结果: {,Z|8@Sl%
type vender pcs y3efie {J
电脑 A 1 OLx;j+p
电脑 A 1 }ILBX4c
光盘 B 2 2hHRitt36
光盘 A 2
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手机 B 3 tR!C8:u
手机 C 3 "]eB2k_>
23、说明:初始化表table1 kXL0
TRUNCATE TABLE table1 )7.)fY$
24、说明:选择从10到15的记录 ew\:&"@2]w
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc &b (*
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三、技巧 pLu5x<
1、1=1,1=2的使用,在SQL语句组合时用的较多 aVR!~hvFs
"where 1=1" 是表示选择全部 "where 1=2"全部不选, "~VKUvDu
如: T={!/y+
if @strWhere !='' f/dJRcDl<
begin Tgpu 9V6
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere >~,~X9
end AJ\gDjj<
else Y2VfJ}%Q
begin &$XTe2
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' uihH")Mo
end -7!L]BcZ.
我们可以直接写成 V?OTP&+J%
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere |M?s[}ll
2、收缩数据库 Kb]}p
--重建索引 >~ *wPoW
DBCC REINDEX ,|*Gr"Q=
DBCC INDEXDEFRAG "EpH02{i
--收缩数据和日志 Xm# +Z`|N
DBCC SHRINKDB q]1p Q)\'p
DBCC SHRINKFILE 4V9BmVS|Th
3、压缩数据库 ;8<HB1 &,
dbcc shrinkdatabase(dbname) 5@RcAQb:
4、转移数据库给新用户以已存在用户权限 (c0L@8L
exec sp_change_users_login 'update_one','newname','oldname' *-ys}sX
go T @^ S:K
5、检查备份集 GG%;~4#2
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' azFJ-0n@"
6、修复数据库 &j~9{ C
ALTER DATABASE [dvbbs] SET SINGLE_USER f@`|2wG
GO @q!T,({kx
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK zsuqRM
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GO |[~S&
ALTER DATABASE [dvbbs] SET MULTI_USER zHKP$k8
GO p"P+8"`
7、日志清除 ^U?Ac=
SET NOCOUNT ON UIU Pi
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DECLARE @LogicalFileName sysname, m=n79]b:N
@MaxMinutes INT, 0to`=;JI
@NewSize INT nP[Z6h
USE tablename -- 要操作的数据库名 %KVmpWku
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ]-t>F
@MaxMinutes = 10, -- Limit on time allowed to wrap log. JFI*Pt;X9
@NewSize = 1 -- 你想设定的日志文件的大小(M) sPc}hG+N
-- Setup / initialize vw>(JCR
DECLARE @OriginalSize int Z;N3mD+\ye
SELECT @OriginalSize = size .RmFYV0,
FROM sysfiles ekY)?$v3
WHERE name = @LogicalFileName 6*B%3\z)
SELECT 'Original Size of ' + db_name() + ' LOG is ' + xq.kH| bH
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 5`3x(=b
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' P$z%:Q
FROM sysfiles ;i.MDW^N
WHERE name = @LogicalFileName Pek[j)g}
CREATE TABLE DummyTrans PCwc=
(DummyColumn char (8000) not null) Zrwd
DECLARE @Counter INT, jv v=
@StartTime DATETIME, y_>DszRN`u
@TruncLog VARCHAR(255) $hc=H
SELECT @StartTime = GETDATE(), &bq1n_
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' xyo~p,(~t
DBCC SHRINKFILE (@LogicalFileName, @NewSize) +@uA
EXEC (@TruncLog) &~;M16XM,e
-- Wrap the log if necessary. +-b'+mF
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired p5qfv>E8)
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 8+Tv@
AND (@OriginalSize * 8 /1024) > @NewSize ]O}e{Q>
BEGIN -- Outer loop. XzIC~}
SELECT @Counter = 0 %h(%M'm?
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) MtwlZg`c3
BEGIN -- update 9:g A0Z
INSERT DummyTrans VALUES ('Fill Log') _1RvK? ;.{
DELETE DummyTrans E5A"sB
SELECT @Counter = @Counter + 1 fn/?I\
END s#<fj#S
EXEC (@TruncLog) X*MK(aV3
END Z^Um\f
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 4<tbZP3/6)
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + rRe^7xGe7
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' s[a\m,
FROM sysfiles "c} en[
WHERE name = @LogicalFileName CT_tJ
DROP TABLE DummyTrans q.R(>ZcV
SET NOCOUNT OFF 4pMp@b
8、说明:更改某个表 =RXeN+
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exec sp_changeobjectowner 'tablename','dbo' 6|'7Mr~\
9、存储更改全部表 DZmVm['l
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch x0)=jp '
@OldOwner as NVARCHAR(128), ZD]{HxGL!
@NewOwner as NVARCHAR(128) U:99w
AS ] 7[#K^
DECLARE @Name as NVARCHAR(128) *.eeiSi{
DECLARE @Owner as NVARCHAR(128) E$z- |-{>
DECLARE @OwnerName as NVARCHAR(128) f99"~)B|
DECLARE curObject CURSOR FOR ez9F!1
select 'Name' = name, oj.J;[-
'Owner' = user_name(uid) G:1QXwq\j
from sysobjects ]#DCO8Vk
where user_name(uid)=@OldOwner u(yN81
order by name y+Nw>\|S
OPEN curObject Q}^Ip7T
FETCH NEXT FROM curObject INTO @Name, @Owner %5+X
WHILE(@@FETCH_STATUS=0) y|+5R5}K
BEGIN T~$Eh6
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if @Owner=@OldOwner _'Jjt9@S
begin (Z @dz
set @OwnerName = @OldOwner + '.' + rtrim(@Name) )H]L/n
exec sp_changeobjectowner @OwnerName, @NewOwner D^>d<LX
end zqrqbqK5R
-- select @name,@NewOwner,@OldOwner 8ZbXGQ
FETCH NEXT FROM curObject INTO @Name, @Owner b3_P??yp
END 3n)Kzexh
close curObject '/XP4B\(E
deallocate curObject .|u`s,\
GO Q=%W-
10、SQL SERVER中直接循环写入数据 $bKXP(
declare @i int E@otV6Wk[@
set @i=1 $?!]?{K
while @i<30 ?7)v:$(G}
begin %Iflf]l
insert into test (userid) values(@i) "oiN8#Hf
set @i=@i+1 jmgkY)rb R
end )c*xKij
小记存储过程中经常用到的本周,本月,本年函数 qT$ IV\;_
Dateadd(wk,datediff(wk,0,getdate()),-1) GK-P6d
Dateadd(wk,datediff(wk,0,getdate()),6) hC8WRxEGq
Dateadd(mm,datediff(mm,0,getdate()),0) Z'9 |
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) u4T$
Dateadd(yy,datediff(yy,0,getdate()),0) eD(5+bm
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) <z%**gP~G
上面的SQL代码只是一个时间段 &-o5lrq
Dateadd(wk,datediff(wk,0,getdate()),-1) raOuD3
Dateadd(wk,datediff(wk,0,getdate()),6) N LQ".mM+
就是表示本周时间段. f U=P$s
下面的SQL的条件部分,就是查询时间段在本周范围内的: :zo5`[P
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 1yz%ud-l
而在存储过程中 9[X'9*,
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) .czUJyFms}
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 2 <OU)rVE4