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。 $-x@P9im
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一、基础 H YA<
1、说明:创建数据库 _BC%98:WP
CREATE DATABASE database-name Ln&'5D#
2、说明:删除数据库 G0e]PMeFl
drop database dbname 06)B<
3、说明:备份sql server q 4Rvr[
--- 创建 备份数据的 device 1$+-?:i C
USE master CP5vo-/)-
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' x-hr64WFK
--- 开始 备份 /y2)<{{I
BACKUP DATABASE pubs TO testBack p'@|Oq&
4、说明:创建新表 Y! 8 I
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 3izGMH_`
根据已有的表创建新表: sN"JVJXi
A:create table tab_new like tab_old (使用旧表创建新表) Ah_,5Z@&R
B:create table tab_new as select col1,col2... from tab_old definition only D]P_tJI
5、说明:删除新表 \E}YtN#
drop table tabname [unK5l4_!
6、说明:增加一个列 ^0x0 rY
Alter table tabname add column col type %$'YP
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。 {Yt@H
7、说明:添加主键: Alter table tabname add primary key(col) \w6A-daD0
说明:删除主键: Alter table tabname drop primary key(col) Z30r|Ufh
8、说明:创建索引:create [unique] index idxname on tabname(col....) G8sxg&bf{
删除索引:drop index idxname ygN4%-[XA
注:索引是不可更改的,想更改必须删除重新建。 WUN|,P`b
9、说明:创建视图:create view viewname as select statement \vKKq/f
删除视图:drop view viewname zw2qv'
10、说明:几个简单的基本的sql语句 L
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选择:select * from table1 where 范围 Tgf\f%,h
插入:insert into table1(field1,field2) values(value1,value2) sYMgi D
删除:delete from table1 where 范围 F"G]afI9+
更新:update table1 set field1=value1 where 范围 fV>12ici
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! Z?@oe-mz
排序:select * from table1 order by field1,field2 [desc] :gwM$2vv
总数:select count as totalcount from table1 VKZZTFmV2)
求和:select sum(field1) as sumvalue from table1 vq?aFX9F
平均:select avg(field1) as avgvalue from table1 P5$L(x%~
最大:select max(field1) as maxvalue from table1 (4GDh%
最小:select min(field1) as minvalue from table1 6g6BE^o\
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11、说明:几个高级查询运算词 ,NA _pvH)
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A: UNION 运算符 j=],n8_i
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。 Ra!Br6
B: EXCEPT 运算符 _ Vo35kA
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。 g)L?C'BG
C: INTERSECT 运算符 A.8[FkiNmD
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。 8AGP*"gI
注:使用运算词的几个查询结果行必须是一致的。 Y|3n^%I
12、说明:使用外连接 w4<n=k
A、left outer join: >Q-"-X1
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。 Y!1x,"O'H
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 =Z(_lLNmh
B:right outer join: 'ZiTjv]
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。 ab!Cu8~v
C:full outer join: i(9 5=t(
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。 n2p(@
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二、提升 8*7,qX
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) l5/!0]/
法一:select * into b from a where 1<>1 pWm==Ds|
法二:select top 0 * into b from a 141G~@-
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) NB.s2I7
insert into b(a, b, c) select d,e,f from b; !k}]` z^d
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) GKg&lM!O$
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 Y9w^F_relL
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. |ctcY*+
4、说明:子查询(表名1:a 表名2:b) zF7*T?3b"
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) @dHQ}Ni
5、说明:显示文章、提交人和最后回复时间 "NMSLqO
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b gK#G8V-,
6、说明:外连接查询(表名1:a 表名2:b) "C~Zl&3
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c <J
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7、说明:在线视图查询(表名1:a ) ],l}J'.8<V
select * from (SELECT a,b,c FROM a) T where t.a > 1; |z
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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 >u0B ~9_E
select * from table1 where time between time1 and time2 4\pUA4
select a,b,c, from table1 where a not between 数值1 and 数值2 `^G?+p2E
9、说明:in 的使用方法 B]lM69Hz
select * from table1 where a [not] in ('值1','值2','值4','值6') {Y6;/".DM
10、说明:两张关联表,删除主表中已经在副表中没有的信息 nX>HRdC
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) u]$e@Vw.
11、说明:四表联查问题:
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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 ..... bMvHAtp
12、说明:日程安排提前五分钟提醒 j96\({;k
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ,?KN;~t#vz
13、说明:一条sql 语句搞定数据库分页 +>BD^[^^
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 MRb6O!$`C
14、说明:前10条记录 h3YWqSj
select top 10 * form table1 where 范围 ?H0"*8C?Y
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.) 5bHS| <
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) gY/p\kwsj
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 H3Zsm)+:
(select a from tableA ) except (select a from tableB) except (select a from tableC) J};=)xLX;
17、说明:随机取出10条数据 Fs 95^T
select top 10 * from tablename order by newid() d#>iFD+
18、说明:随机选择记录 6%\&m|S
select newid() wticA#mb
19、说明:删除重复记录 >&?k^nI}J
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) [IRWm N-
20、说明:列出数据库里所有的表名 '>U&B}
select name from sysobjects where type='U' #k/NS
21、说明:列出表里的所有的 ^)i1b:4
select name from syscolumns where id=object_id('TableName') B4kJ 7Pdny
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。 #bZT&YE^
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 hTS?+l
显示结果: [39
type vender pcs YkJnZ_k/P
电脑 A 1 (d?sFwOt\
电脑 A 1 ZGgM-O1
光盘 B 2 L; (J6p]h
光盘 A 2 T*bBw
手机 B 3 _I<LB0kgf.
手机 C 3 tEl_a~s*3?
23、说明:初始化表table1 /s|4aro
TRUNCATE TABLE table1 +)U>mm,
24、说明:选择从10到15的记录 --BS/L-
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc C/{%f,rU
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三、技巧 Bf+7;4-
1、1=1,1=2的使用,在SQL语句组合时用的较多 4lsg%b6_%,
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 3?Tk[m1b
如: Dqg~g|(Q<
if @strWhere !='' p`mNy
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begin i8+[-mh
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere tO8<N'TD
end /5&'U!:+
else SMIr@*R
begin u0?,CQPL
set @strSQL = 'select count(*) as Total from [' + @tblName + ']'
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end N799@:.
我们可以直接写成 $^ZugD
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere oJln"-M1nx
2、收缩数据库 dHJ#xmE!pP
--重建索引 m6iQB\ \
DBCC REINDEX =ec"G2$?"
DBCC INDEXDEFRAG |x/00XhS
--收缩数据和日志 uh
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DBCC SHRINKDB |4?O4QN
DBCC SHRINKFILE M.h8Kr!.
3、压缩数据库 w^N3Ma
dbcc shrinkdatabase(dbname) s;!Tz)
4、转移数据库给新用户以已存在用户权限 p)y'a+|7
exec sp_change_users_login 'update_one','newname','oldname' -V'h>K
go (I0QwB
5、检查备份集 8TV
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RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ?o883!&v
6、修复数据库 vC|V8ea
ALTER DATABASE [dvbbs] SET SINGLE_USER xa]e9u%
GO ['#3GJz-
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK )DwHLaLW
GO @yxF/eeEy+
ALTER DATABASE [dvbbs] SET MULTI_USER 8D5v'[j-
GO 0k):OVfm=
7、日志清除 0fP-[7P
SET NOCOUNT ON 60Szn]z'8[
DECLARE @LogicalFileName sysname, j _p|>f<}
@MaxMinutes INT, 2PVtyV3;
@NewSize INT &vHfuM`
USE tablename -- 要操作的数据库名 $CP_oEb
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ,HHCgN
@MaxMinutes = 10, -- Limit on time allowed to wrap log. KXvBJA$
@NewSize = 1 -- 你想设定的日志文件的大小(M) ReZ&SNJ
-- Setup / initialize ZgH(,g,TU
DECLARE @OriginalSize int RM `zxFn
SELECT @OriginalSize = size dVe
FROM sysfiles 45H(.}&f
WHERE name = @LogicalFileName *r|)@K|
SELECT 'Original Size of ' + db_name() + ' LOG is ' + C)v*L#{%
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + HHXm
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CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' MzX4/*ba
FROM sysfiles lN,)T%[0-
WHERE name = @LogicalFileName MB:*WA&
CREATE TABLE DummyTrans *@SZ0
(DummyColumn char (8000) not null) Im<(
DECLARE @Counter INT, d^W1;0
@StartTime DATETIME, ,'z=cB`+o
@TruncLog VARCHAR(255) eR*y<K(d
SELECT @StartTime = GETDATE(), Aat-938FP6
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' #s]'2O
DBCC SHRINKFILE (@LogicalFileName, @NewSize) VY]L<4BfGL
EXEC (@TruncLog) [)L) R`
-- Wrap the log if necessary. l.@&B@5F
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired -er8(snDQ
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) Yj/[I\I"m
AND (@OriginalSize * 8 /1024) > @NewSize nQ}$jOU&
BEGIN -- Outer loop. u{d\3-]/
SELECT @Counter = 0 ~
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WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) Tn"/EO^N
BEGIN -- update T2p;#)dP
INSERT DummyTrans VALUES ('Fill Log') }[c,/NH
DELETE DummyTrans zd-qQ.j0
SELECT @Counter = @Counter + 1 ;[R#:Rk
END [Z$E^QAP
EXEC (@TruncLog) \\{+t<?J
END RZrQ^tI3"
SELECT 'Final Size of ' + db_name() + ' LOG is ' + Wv4o:_}
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ]UFbG40Zo
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' WO<a^g
{
FROM sysfiles
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WHERE name = @LogicalFileName 71(C@/J
DROP TABLE DummyTrans ?@LqrKj11
SET NOCOUNT OFF GiGXV @dq
8、说明:更改某个表 . ]D7Il
exec sp_changeobjectowner 'tablename','dbo' #Rx|oSc}
9、存储更改全部表 iwS55o
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch |z%:{
@OldOwner as NVARCHAR(128), }V I}O{
@NewOwner as NVARCHAR(128) j|X>:!4r
AS 2ms@CQy(00
DECLARE @Name as NVARCHAR(128) zc#$hIi
DECLARE @Owner as NVARCHAR(128) b<1+q{0r
DECLARE @OwnerName as NVARCHAR(128) IyJHKDFk
DECLARE curObject CURSOR FOR nlsif
select 'Name' = name, ~]LkQQ'
'Owner' = user_name(uid) 8\])p sb9
from sysobjects &8R!`uh1
where user_name(uid)=@OldOwner :,[=g$CT:
order by name d]!`II
OPEN curObject ~f5g\n;
FETCH NEXT FROM curObject INTO @Name, @Owner ^p}|""\j
WHILE(@@FETCH_STATUS=0) SoPiEq
BEGIN N:nhS3N<L
if @Owner=@OldOwner $7
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begin G>>TB{}
set @OwnerName = @OldOwner + '.' + rtrim(@Name) &w7Ev21
exec sp_changeobjectowner @OwnerName, @NewOwner *Tyr
end 2n|]&D3V"'
-- select @name,@NewOwner,@OldOwner I`-N]sf^
FETCH NEXT FROM curObject INTO @Name, @Owner @&fAR2
END Rt=zqfJ
close curObject Q-7C'|
deallocate curObject j,@@[{tu
GO LUN"p#1
10、SQL SERVER中直接循环写入数据 -Mx\W|YK
declare @i int wu53e= /
set @i=1 YOE!+MiO
while @i<30 GX-V|hLaGX
begin oTLA&dy@
insert into test (userid) values(@i) .m/$ku{/J
set @i=@i+1 `j)S7KN
end L$rMfeS
小记存储过程中经常用到的本周,本月,本年函数 ]R?{9H|jwE
Dateadd(wk,datediff(wk,0,getdate()),-1) glo Y@k~
Dateadd(wk,datediff(wk,0,getdate()),6) bjCO@t
Dateadd(mm,datediff(mm,0,getdate()),0) q"C(`S.@
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ]~!?(d!J/
Dateadd(yy,datediff(yy,0,getdate()),0) u zgQ_
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) , tb\^
上面的SQL代码只是一个时间段 l+HF+v$
Dateadd(wk,datediff(wk,0,getdate()),-1) ~>-MVp
Dateadd(wk,datediff(wk,0,getdate()),6) .0]\a~x
就是表示本周时间段. *}<