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。 (q
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一、基础 I@M3u/7
1、说明:创建数据库 X<8
CREATE DATABASE database-name 5Z<y||=
2、说明:删除数据库 -Uj3?W
drop database dbname 8TE2q Pm
3、说明:备份sql server phc9esz
--- 创建 备份数据的 device JtbwY@R
USE master nf2[hx@=U
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' k^i\<@v
--- 开始 备份 m\DI6O"u'
BACKUP DATABASE pubs TO testBack C25EIIdRb
4、说明:创建新表 UVUoXv)N
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) X$0&tmum
根据已有的表创建新表: #Aver]eK
A:create table tab_new like tab_old (使用旧表创建新表) TGSkJ 1Lx
B:create table tab_new as select col1,col2... from tab_old definition only >OotgJnhC
5、说明:删除新表 XD8Q2un
drop table tabname 7lH.>n
6、说明:增加一个列 mE)I(< %
Alter table tabname add column col type 1:j[p=Q&
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。 +#LD@)G
7、说明:添加主键: Alter table tabname add primary key(col) 7,IH7l|G
说明:删除主键: Alter table tabname drop primary key(col) ^!j,d_)b!
8、说明:创建索引:create [unique] index idxname on tabname(col....) D>`lN
删除索引:drop index idxname ~6!TMVr
注:索引是不可更改的,想更改必须删除重新建。 qi]"`\
9、说明:创建视图:create view viewname as select statement L
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删除视图:drop view viewname a
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10、说明:几个简单的基本的sql语句 g54b}vzm
选择:select * from table1 where 范围 $OP w$
插入:insert into table1(field1,field2) values(value1,value2) @ r G=>??k
删除:delete from table1 where 范围 g?1! /+
更新:update table1 set field1=value1 where 范围 #k/NS
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! .?NraydwV
排序:select * from table1 order by field1,field2 [desc] 'g#EBy
总数:select count as totalcount from table1 8;q2W
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求和:select sum(field1) as sumvalue from table1 NU/:jr.W#
平均:select avg(field1) as avgvalue from table1 '.5_L8
最大:select max(field1) as maxvalue from table1 b!gvvg<
最小:select min(field1) as minvalue from table1 h3BDHz,
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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 UR'P,
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。 fb;y*-?#
B: EXCEPT 运算符 =H)"t:xE
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。 cwC-)#R']
C: INTERSECT 运算符 fKQq]&~
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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。 k=``Avp?
注:使用运算词的几个查询结果行必须是一致的。 <x O"
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12、说明:使用外连接 #57D10j
A、left outer join: E5`KUMZkq
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。 r{
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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 W"&Y7("y
B:right outer join: Qk#`e
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。 J{qpGRQNa
C:full outer join: (N/KP+J$n
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。 p)y'a+|7
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二、提升 k*"FMJG_
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) }35HKgqX
法一:select * into b from a where 1<>1 z]33_[G1U
法二:select top 0 * into b from a IuN:*P
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) F?*ko,
insert into b(a, b, c) select d,e,f from b; KoF_G[m
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) Unc_e
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ,o68xfdZVW
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. riz[AAB
4、说明:子查询(表名1:a 表名2:b) vd ]75
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) C'oNGOEd
5、说明:显示文章、提交人和最后回复时间 V0)F/qY
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b ;:#g\|(<+
6、说明:外连接查询(表名1:a 表名2:b) |a{~Imz{
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c C)v*L#{%
7、说明:在线视图查询(表名1:a ) ^!yJ;'H\
select * from (SELECT a,b,c FROM a) T where t.a > 1; jp|1S^b
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 wD|I^y;
select * from table1 where time between time1 and time2 d^W1;0
select a,b,c, from table1 where a not between 数值1 and 数值2 =*Ru2
9、说明:in 的使用方法 VyWPg7}e
select * from table1 where a [not] in ('值1','值2','值4','值6') dp~] Wx
10、说明:两张关联表,删除主表中已经在副表中没有的信息 8sz|9~
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) +#=l{_Z,ZJ
11、说明:四表联查问题: +x_9IvaW&?
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 ..... N&K`bmtD
12、说明:日程安排提前五分钟提醒 u{d\3-]/
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 +204.Yj?D
13、说明:一条sql 语句搞定数据库分页 T2p;#)dP
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 Uk@'[_1z
14、说明:前10条记录 KE*8Y4#9
select top 10 * form table1 where 范围 l0G sY.~,
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.) O;m@fS2%3
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) d&apu{
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 Lj#K^c Ee
(select a from tableA ) except (select a from tableB) except (select a from tableC) V9cKl[
17、说明:随机取出10条数据 Pt^SlX^MM
select top 10 * from tablename order by newid() 3qNLosm#M
18、说明:随机选择记录 iwS55o
select newid() *Z:'jV<
19、说明:删除重复记录 [8$K i$;
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) uFl19
20、说明:列出数据库里所有的表名 N,F$^ q6
select name from sysobjects where type='U' nlsif
21、说明:列出表里的所有的 ^oYudb^%
select name from syscolumns where id=object_id('TableName') yG..B
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。 l:$i}.C
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type /@qnEP%
显示结果: /CfgxPo
type vender pcs (W'.vEl
电脑 A 1 ~P;KO40K
电脑 A 1 ,UE>@;]
光盘 B 2 5i|DJ6
光盘 A 2 ).D+/D/"2
手机 B 3 Rt=zqfJ
手机 C 3 \Jy/
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23、说明:初始化表table1 LUN"p#1
TRUNCATE TABLE table1 R m^$Dn
24、说明:选择从10到15的记录 BfOQ/k))
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc S%{^@L+V
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三、技巧 E=eK(t(8
1、1=1,1=2的使用,在SQL语句组合时用的较多 TP R$oO2
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 3I):W9$Qp
如: {$H-7-O$
if @strWhere !='' TpIx!R9
begin n4%ZR~9WH
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 3 jR I@
end vA"MTncv
else _`- trE.
begin H.=S08c3kA
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' F(}~~EtPHo
end +0Z,#b
我们可以直接写成 PqDffZ^z
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere e:uk``\
2、收缩数据库 8;\
--重建索引 |S0nR<x-M
DBCC REINDEX mi]bS
DBCC INDEXDEFRAG ~4^~w#R
--收缩数据和日志 AS?
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DBCC SHRINKDB OAw- -rl
DBCC SHRINKFILE 68 \73L=
3、压缩数据库 3[F9qDAy
dbcc shrinkdatabase(dbname) PXrv2q[5?
4、转移数据库给新用户以已存在用户权限 (<KFA,
exec sp_change_users_login 'update_one','newname','oldname' Wb{0UkApJ
go !!:mjq<0
5、检查备份集 v1O 1-aM
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 0(|Yy/Yq
6、修复数据库
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ALTER DATABASE [dvbbs] SET SINGLE_USER ?%A9}"q]
GO tN1xZW:
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK YMr2|VEU[
GO P+:DLex
ALTER DATABASE [dvbbs] SET MULTI_USER ? dh
GO !*G%vOa
7、日志清除 {3`cSm6c
SET NOCOUNT ON H5!e/4iz
DECLARE @LogicalFileName sysname, i9koh3R\
@MaxMinutes INT, f>hA+
@NewSize INT sOqT*gwr:
USE tablename -- 要操作的数据库名 NpLZ
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SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 N3(.7mxo
@MaxMinutes = 10, -- Limit on time allowed to wrap log. w&[&ZDsK
@NewSize = 1 -- 你想设定的日志文件的大小(M) i z%wozf
-- Setup / initialize B?
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DECLARE @OriginalSize int h<<uef9
SELECT @OriginalSize = size =n<Lbl(7
FROM sysfiles )lZoXt_3
WHERE name = @LogicalFileName x:$ xtu
SELECT 'Original Size of ' + db_name() + ' LOG is ' + \"pp-str
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + \k
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CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' !9t,#?!
FROM sysfiles IhjZ{oV/@
WHERE name = @LogicalFileName 2!Qg1hM
CREATE TABLE DummyTrans )_olJCdaP^
(DummyColumn char (8000) not null) %k'>bmJ
DECLARE @Counter INT, '\M]$`Et
@StartTime DATETIME, R8-=N+hX
@TruncLog VARCHAR(255) 8I[=iU7]l
SELECT @StartTime = GETDATE(), oJ?,X^~_
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' Ggk#>O G
DBCC SHRINKFILE (@LogicalFileName, @NewSize) Ge7Uety
EXEC (@TruncLog) E?-
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-- Wrap the log if necessary. r yNe=9p
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 4<V}Aj8l
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) rS8}(lf
AND (@OriginalSize * 8 /1024) > @NewSize UZpQ%~/
BEGIN -- Outer loop. 0bG#'.-
SELECT @Counter = 0 M}e}3w
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) *#9?9SYSk
BEGIN -- update #y-R*4G
INSERT DummyTrans VALUES ('Fill Log') 0^vz /y1c
DELETE DummyTrans +rJDDIb
SELECT @Counter = @Counter + 1 zY9CoadZ
END 2m^qXE$
EXEC (@TruncLog) iNr&;
END 6UI6E)g
SELECT 'Final Size of ' + db_name() + ' LOG is ' + Ya4yW9*
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + iPdS>ee
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' q P0UcG
FROM sysfiles ~BiLzT1,
WHERE name = @LogicalFileName 1~Z
DROP TABLE DummyTrans "U!Vdt2vp
SET NOCOUNT OFF y+p"5s"
8、说明:更改某个表 tOX-vQ
exec sp_changeobjectowner 'tablename','dbo' 0avtfQ +f
9、存储更改全部表 {n&GZG"f
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch IrUoAQ2xpG
@OldOwner as NVARCHAR(128), MOPHu
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@NewOwner as NVARCHAR(128) jx{
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AS Tm$8\c4V:*
DECLARE @Name as NVARCHAR(128) zm8k,e +5-
DECLARE @Owner as NVARCHAR(128) `=S%!akj
DECLARE @OwnerName as NVARCHAR(128) V-3;7
DECLARE curObject CURSOR FOR Po&'#TC1
select 'Name' = name, 'P*OzZ4>$
'Owner' = user_name(uid) T"t.t%(8
from sysobjects Y9I|s{~
where user_name(uid)=@OldOwner k!bG![Ie|
order by name +@c$n`>)
OPEN curObject Sk:x.oOZ
FETCH NEXT FROM curObject INTO @Name, @Owner * =*\w\
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WHILE(@@FETCH_STATUS=0) [nG[ x|;|
BEGIN U&43/;<,
if @Owner=@OldOwner X#Ob^E%J
begin 3,EtyJ3[Bh
set @OwnerName = @OldOwner + '.' + rtrim(@Name) g}S%D(~
exec sp_changeobjectowner @OwnerName, @NewOwner 6v74mIRn'?
end 9kwiG7V1
-- select @name,@NewOwner,@OldOwner 'y5H%I!
FETCH NEXT FROM curObject INTO @Name, @Owner \GV'{W+o2
END M2;6Cz>,P
close curObject OsW*@v(
deallocate curObject =v0w\(
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GO bN6i *)}
10、SQL SERVER中直接循环写入数据 gLY15v4?
declare @i int cltx(C>
set @i=1 ty:{e]e
while @i<30 .s?^y+e_
begin Z
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insert into test (userid) values(@i) :Gzp
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set @i=@i+1 2R
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end CMyz!jZ3
小记存储过程中经常用到的本周,本月,本年函数 Q5l+-
Dateadd(wk,datediff(wk,0,getdate()),-1) I-=Ieq"R9
Dateadd(wk,datediff(wk,0,getdate()),6) I0><IaFy
Dateadd(mm,datediff(mm,0,getdate()),0) u%6b|M@P
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) $Yp.BE<}
Dateadd(yy,datediff(yy,0,getdate()),0) j/F('r~L
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) gyPwNE
上面的SQL代码只是一个时间段 <:&{ c-f/
Dateadd(wk,datediff(wk,0,getdate()),-1)
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Dateadd(wk,datediff(wk,0,getdate()),6) h(GSM'v
就是表示本周时间段. 6!USSipn
下面的SQL的条件部分,就是查询时间段在本周范围内的: )/Gi-::
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) MttFB;Tp
而在存储过程中 ; xQhq*
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) K r<UPr
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) K`60[bdp