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。 +YCWoX2
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一、基础 g_tEUaiK
1、说明:创建数据库 Fgwe`[
CREATE DATABASE database-name 9_&]7ABV
2、说明:删除数据库 $E:z*~?
drop database dbname ^Vh^Z)gGi
3、说明:备份sql server %O(W;O
--- 创建 备份数据的 device "AMw o(Yi
USE master bfJ<~ss/
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' Q(1R=4?.Z
--- 开始 备份 [!KsAsmk
BACKUP DATABASE pubs TO testBack *}(B"FSO
4、说明:创建新表 r_'];
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 1T~`$zS7
根据已有的表创建新表: d*([!!i
A:create table tab_new like tab_old (使用旧表创建新表) Td^62D;
B:create table tab_new as select col1,col2... from tab_old definition only /-@F|,O)$n
5、说明:删除新表 V~o'L#a
drop table tabname #gf0*:p
6、说明:增加一个列 oM#+Z
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Alter table tabname add column col type u,YmCEd_V
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。 8h}1t4k
7、说明:添加主键: Alter table tabname add primary key(col) `N}'5{I
说明:删除主键: Alter table tabname drop primary key(col) 9*n?V ;E
8、说明:创建索引:create [unique] index idxname on tabname(col....) j9Z1=z
删除索引:drop index idxname ,FRa6;
注:索引是不可更改的,想更改必须删除重新建。 XNvlx4
9、说明:创建视图:create view viewname as select statement i}<fg*6@E
删除视图:drop view viewname Uul5h8F
10、说明:几个简单的基本的sql语句 ky]L`w
选择:select * from table1 where 范围 vf?m6CMU!
插入:insert into table1(field1,field2) values(value1,value2) Jl6biJx
删除:delete from table1 where 范围 11fV|b%
更新:update table1 set field1=value1 where 范围 mv*M2NuhT
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! Ve"M8-{oKk
排序:select * from table1 order by field1,field2 [desc] =7~;*Ts
总数:select count as totalcount from table1 #.}&6ZP
求和:select sum(field1) as sumvalue from table1 *a(GG
平均:select avg(field1) as avgvalue from table1 [Q8vS ;.
最大:select max(field1) as maxvalue from table1 <1~_nt~(*
最小:select min(field1) as minvalue from table1 [*ug:PG
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11、说明:几个高级查询运算词 {ueDwnZ
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A: UNION 运算符 J}@.f-W\j
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。 _t X1z^
B: EXCEPT 运算符 FPE6H:'
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。 #xq|/JWs
C: INTERSECT 运算符 YcSPU(
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。 vhU
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注:使用运算词的几个查询结果行必须是一致的。 Q? Xqf7y
12、说明:使用外连接 -3y
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A、left outer join: a63Ud<_a7
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。 01%0u8U
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 gHWsKE
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B:right outer join: m{yq.H[X
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。 NeewV=[%
C:full outer join: W{}M${6&
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。 H,!yG5yF
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二、提升 [F27i#'I]
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) gPpk0LZi
法一:select * into b from a where 1<>1 RS{E|
法二:select top 0 * into b from a 3XUie;*`
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) }?U
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insert into b(a, b, c) select d,e,f from b; ?IiFFfs
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) A;;OGJ,!\
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 CT=5V@_u\
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. immf\
4、说明:子查询(表名1:a 表名2:b) soB_j
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) 4)snt3k
5、说明:显示文章、提交人和最后回复时间 BL\H@D
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b p<RIvSqM
6、说明:外连接查询(表名1:a 表名2:b) BDi+*8
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 2d OUY
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7、说明:在线视图查询(表名1:a ) mP
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select * from (SELECT a,b,c FROM a) T where t.a > 1; %LnG^L
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 A{Y/eG8
select * from table1 where time between time1 and time2 Ht~YSQ~:y
select a,b,c, from table1 where a not between 数值1 and 数值2 A(JgAV1{
9、说明:in 的使用方法 Qer}eg`R
select * from table1 where a [not] in ('值1','值2','值4','值6') bg*@N
10、说明:两张关联表,删除主表中已经在副表中没有的信息 SXV
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delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) =d
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11、说明:四表联查问题: !@)tkhP
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 ..... drB$q[Ak9
12、说明:日程安排提前五分钟提醒 (%]M a
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 '"V]>)
13、说明:一条sql 语句搞定数据库分页 o~'UWU'#
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 1L_(n
14、说明:前10条记录 h7}P5z0F
select top 10 * form table1 where 范围 ;'4Kg@/
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) }~ga86:n0
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) n=h!V$X
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 ^QTkre
(select a from tableA ) except (select a from tableB) except (select a from tableC) |f[:mO
17、说明:随机取出10条数据 U;U19[]
select top 10 * from tablename order by newid() RXhT{Ho(>
18、说明:随机选择记录 vPu{xy
select newid() M9(Kxux#
19、说明:删除重复记录 QLH6Nmk
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) +Jq~39
20、说明:列出数据库里所有的表名 zj;KtgcE
select name from sysobjects where type='U' ,Mu"r!MK
21、说明:列出表里的所有的 )dRBI)P
select name from syscolumns where id=object_id('TableName') KC-@2,c9V
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。 };~I#X
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 \.`{nq
显示结果: 9+frxD&pO
type vender pcs
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电脑 A 1 kNUNh[
电脑 A 1 4AN(4"$N
光盘 B 2 ek0,@Vg9
光盘 A 2 F#l!LER^1g
手机 B 3 N8`q.;qewz
手机 C 3 t[bZg9;
23、说明:初始化表table1 NKu*kL}W=
TRUNCATE TABLE table1 frbeCBP&)
24、说明:选择从10到15的记录 k{+Gv}Y
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 5G WC
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三、技巧 2PVQSwW:
1、1=1,1=2的使用,在SQL语句组合时用的较多
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"where 1=1" 是表示选择全部 "where 1=2"全部不选, !u%XvxJwDb
如: HVM(LHm=:
if @strWhere !='' NYF
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begin O['5/:-
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 'X1/tB8*
end [gE2;J0*
else d>`s+B9K0
begin Jgzg[6
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' GuRJ
end 7j{63d`2
我们可以直接写成 gib;> nuBK
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ]iH~1 [
2、收缩数据库 x@,B))WlGr
--重建索引 NGuRyZp69&
DBCC REINDEX jH]?vpP
DBCC INDEXDEFRAG JO|xX<#:
--收缩数据和日志 d2<+Pp
DBCC SHRINKDB h[j(@P
DBCC SHRINKFILE Xwk_QFv3
3、压缩数据库 Vg8c}>7
dbcc shrinkdatabase(dbname) 4mwA o
4、转移数据库给新用户以已存在用户权限 _{0IX
exec sp_change_users_login 'update_one','newname','oldname' %9`\7h7K
go "5$2b>_UE
5、检查备份集 Y-:dPc{
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' v\Xyz
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6、修复数据库 @"BkLF
ALTER DATABASE [dvbbs] SET SINGLE_USER #w]@yL]|is
GO +Uf+`
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK Te&5IB-
GO ~#9(Q
ALTER DATABASE [dvbbs] SET MULTI_USER !l#n.Fx&3
GO FKkL%:?
7、日志清除 ,Q>wcE6v
SET NOCOUNT ON (&-!l2
DECLARE @LogicalFileName sysname, ]s^Pw>/`
@MaxMinutes INT, '&Tq/;Ml
@NewSize INT iKe68kx
USE tablename -- 要操作的数据库名 CJ[^Fi?CH
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 |C.[eHe&D
@MaxMinutes = 10, -- Limit on time allowed to wrap log. APL #-`XC
@NewSize = 1 -- 你想设定的日志文件的大小(M) TWo.c _l
-- Setup / initialize DzG$\%G2R}
DECLARE @OriginalSize int \kVi&X=q:
SELECT @OriginalSize = size mpDQhD[n
FROM sysfiles aA&}=lm
WHERE name = @LogicalFileName 5jK9cF$>
SELECT 'Original Size of ' + db_name() + ' LOG is ' + g,""j`
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + =&v&qne9
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' ]sV) '-
FROM sysfiles CC{{@
WHERE name = @LogicalFileName ev%}\^Vl[
CREATE TABLE DummyTrans 8/+x1, S%
(DummyColumn char (8000) not null) #)EVi7UP
DECLARE @Counter INT, j\@osjUu
@StartTime DATETIME, 'mU7N<Q$qQ
@TruncLog VARCHAR(255) {qPu}?0
SELECT @StartTime = GETDATE(), 9|1J pb
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' *WZ?C|6+
DBCC SHRINKFILE (@LogicalFileName, @NewSize) IRB BLXv7\
EXEC (@TruncLog) }C9P--
-- Wrap the log if necessary. g)Dg=3+>
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired Sv|jR r'
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) '7/c7m/$X<
AND (@OriginalSize * 8 /1024) > @NewSize R7~#7qKQB
BEGIN -- Outer loop. X1~ WQ?ww
SELECT @Counter = 0 Y8%*S%yO
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) vHxLn/
BEGIN -- update bf-V Q7
INSERT DummyTrans VALUES ('Fill Log') y?yWM8
DELETE DummyTrans @DA.$zn&
SELECT @Counter = @Counter + 1 =/L;}m)7
END cuo'V*nWQ
EXEC (@TruncLog) ":,J<|Oy
END ok<!/"RX$
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 4WZ"8
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 4Q
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CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' $WHmG!)*
FROM sysfiles B0eKj=y;
WHERE name = @LogicalFileName Z2hIoCT
DROP TABLE DummyTrans `%A>{ A"
SET NOCOUNT OFF {/PiX1mn
8、说明:更改某个表 e95@4f^K2
exec sp_changeobjectowner 'tablename','dbo' 6=i@ttAK
9、存储更改全部表 23~KzC
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch \S`|7JYW
@OldOwner as NVARCHAR(128), x4nmDEpa
@NewOwner as NVARCHAR(128) 7\sR f/
AS ^Y-
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DECLARE @Name as NVARCHAR(128) vK~tgZ&
DECLARE @Owner as NVARCHAR(128)
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DECLARE @OwnerName as NVARCHAR(128) "Zq)y_1
DECLARE curObject CURSOR FOR K"U[OZC`
select 'Name' = name, @Zov&01
'Owner' = user_name(uid) -iJ @K
from sysobjects ;Alw`'
where user_name(uid)=@OldOwner EwH_k
order by name 7z^\}&
OPEN curObject t~@~XI5
FETCH NEXT FROM curObject INTO @Name, @Owner w*7BiZ{s<
WHILE(@@FETCH_STATUS=0) x;p7n2_
BEGIN -P7JaH/Q
if @Owner=@OldOwner [Uw/;Kyh
begin hj|P*yKV
set @OwnerName = @OldOwner + '.' + rtrim(@Name) U|}Bk/0.
exec sp_changeobjectowner @OwnerName, @NewOwner b Q6<R4
end dyMj=e
-- select @name,@NewOwner,@OldOwner WyDL ah^/
FETCH NEXT FROM curObject INTO @Name, @Owner Dhy@!EOS
END vgvJ6$#
close curObject rLzN#Zoi
deallocate curObject 8KhE`C9z
GO `oUuAL
10、SQL SERVER中直接循环写入数据 mhZ60 RW
declare @i int iF1E 5{dH
set @i=1 "<5su5]
while @i<30 60r4%>d
begin >qhoGg
insert into test (userid) values(@i) zOzobd
set @i=@i+1 ^ H )nQ
end
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小记存储过程中经常用到的本周,本月,本年函数 HHU0Nku@ho
Dateadd(wk,datediff(wk,0,getdate()),-1) Q1?09
Dateadd(wk,datediff(wk,0,getdate()),6) x]%'^7#v)
Dateadd(mm,datediff(mm,0,getdate()),0) KaGG4?=V
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) \6z_;
Dateadd(yy,datediff(yy,0,getdate()),0) +{F2hEYP
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) vPbmQh ex
上面的SQL代码只是一个时间段 3
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Dateadd(wk,datediff(wk,0,getdate()),-1) Fv(1A_~IS
Dateadd(wk,datediff(wk,0,getdate()),6) mzkv/
就是表示本周时间段. r p^Gk
下面的SQL的条件部分,就是查询时间段在本周范围内的: <>tQa5;
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) NiCB.a
而在存储过程中 !?u{2D
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ~gAp`Q
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) ;mw$(ZKa#