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。 G{[w+ObX
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一、基础 PV#h_X<l%
1、说明:创建数据库 HVus\s\&y%
CREATE DATABASE database-name |Lg2;P7\
2、说明:删除数据库 WkiT,(i
drop database dbname -7&ywgxl
3、说明:备份sql server +\Vw:~e
--- 创建 备份数据的 device U^KWRqt
USE master ^"7-`<J
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' =J1V?x=l@
--- 开始 备份 _h<rVcl!wX
BACKUP DATABASE pubs TO testBack $\ZWQct
4、说明:创建新表 ;<0vvP|
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) n5C,Z!)z
根据已有的表创建新表: RVAku
A:create table tab_new like tab_old (使用旧表创建新表) _b<;n|^
B:create table tab_new as select col1,col2... from tab_old definition only KyrZ&E.`
5、说明:删除新表 9.(|ri
drop table tabname ,+df=>$W
6、说明:增加一个列 AM=,:k$
Alter table tabname add column col type )ItABl[{
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。 [ifw}(
7、说明:添加主键: Alter table tabname add primary key(col) 0JtM|Mg
说明:删除主键: Alter table tabname drop primary key(col) F?'
8、说明:创建索引:create [unique] index idxname on tabname(col....) .bY>++CAPA
删除索引:drop index idxname LC]0c)v#
注:索引是不可更改的,想更改必须删除重新建。 /4(HVua
9、说明:创建视图:create view viewname as select statement }~W/NP_F
删除视图:drop view viewname L91vp'+2
10、说明:几个简单的基本的sql语句 d_we?DZ|
选择:select * from table1 where 范围 a_!H_J
插入:insert into table1(field1,field2) values(value1,value2) N
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删除:delete from table1 where 范围
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更新:update table1 set field1=value1 where 范围 JRC2+BU
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查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! |?J57(
排序:select * from table1 order by field1,field2 [desc] <B>qEa_I
总数:select count as totalcount from table1 >bWpj8Kv
求和:select sum(field1) as sumvalue from table1 FNUs
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平均:select avg(field1) as avgvalue from table1 'GezIIaH
最大:select max(field1) as maxvalue from table1 Jd/d\P
最小:select min(field1) as minvalue from table1 $B?8\>_?
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11、说明:几个高级查询运算词 0p.MH~mx
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A: UNION 运算符 3ux7^au
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。 gOnZ#
B: EXCEPT 运算符 F_0D)H)N@
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_@6!R2
C: INTERSECT 运算符 Khd A;bF
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。 445JOP
注:使用运算词的几个查询结果行必须是一致的。 _*UI}JtlS
12、说明:使用外连接 :q3w;B~
A、left outer join: 3:Nc`tM_
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。 3PvxU|*F
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 1\,k^Je7
B:right outer join: Gjeb)Y6N
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。 g"" 1\rc=
C:full outer join: 8nBYP+t,e
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。 #Hr'plg
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二、提升 @8{8|P
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ]h1.1@ >xc
法一:select * into b from a where 1<>1 i. )^}id
法二:select top 0 * into b from a ].d%R a:{
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 517"x@6Q
insert into b(a, b, c) select d,e,f from b; cZ)JvU9]
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) d#+Nef5
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 Ps.xY;Y
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. G^ k8Or2
4、说明:子查询(表名1:a 表名2:b) oJNQdW[
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) 8y5"X"U
5、说明:显示文章、提交人和最后回复时间 9Vq
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b j]&Qai~}Y
6、说明:外连接查询(表名1:a 表名2:b) 4tUoK[p
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c Jc?zX8>Ae:
7、说明:在线视图查询(表名1:a ) o|d:rp!^
select * from (SELECT a,b,c FROM a) T where t.a > 1; 7]Qxt%7/>
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 #Tzs9Bkaca
select * from table1 where time between time1 and time2 XM5)|D
select a,b,c, from table1 where a not between 数值1 and 数值2 VF11eZ"
9、说明:in 的使用方法 Tv'1IE
select * from table1 where a [not] in ('值1','值2','值4','值6') =D0d+b6
10、说明:两张关联表,删除主表中已经在副表中没有的信息 @TW:6v`
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) _,0.h*c
11、说明:四表联查问题: E>
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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 ..... |qguLab(
12、说明:日程安排提前五分钟提醒 WFc4(Kl
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 p@q20>^u
13、说明:一条sql 语句搞定数据库分页 i[LnU#+
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 c}$>UhLe
14、说明:前10条记录 6oQ7u90z*
select top 10 * form table1 where 范围 N/WtQSl
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.) Zs}h>$E5_B
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) #tUhul/O
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 >pZ_
(select a from tableA ) except (select a from tableB) except (select a from tableC) p q?# X0
17、说明:随机取出10条数据 F$4=7Njv
select top 10 * from tablename order by newid() ~t2"L|i
18、说明:随机选择记录 U) xeta+
select newid() %!-t7K^mFq
19、说明:删除重复记录 k>MXOUaW.
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) jqvw<+#
20、说明:列出数据库里所有的表名 ~}p k^FA
select name from sysobjects where type='U' E`HA0/
21、说明:列出表里的所有的 s\3]0n9
select name from syscolumns where id=object_id('TableName') h*KDZ+{)
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 A #SO}c
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type
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显示结果: Ow1+zltgj-
type vender pcs "i&n;8?Y
电脑 A 1 a'-xCV|^
电脑 A 1 r
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光盘 B 2 )IK%Dg(v
光盘 A 2 E)Qg^DHP/
手机 B 3
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手机 C 3 q2|z
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23、说明:初始化表table1 JcP<@bb>B
TRUNCATE TABLE table1 HL[V}m
24、说明:选择从10到15的记录 YH%U$eS#g
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc ,1|=_M31
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三、技巧 QHje}
1、1=1,1=2的使用,在SQL语句组合时用的较多 $B>L_~cS
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ~FI} [6Dd
如: cuG;1,?b
if @strWhere !='' l0yflFGr
begin y#Nrq9r:
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere S]T71W<i
end P*Jk 8MK#G
else gBI?dw
begin Yx. t+a-
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' $hk_v~zM
end >>R)?24,<
我们可以直接写成 {hO|{vz
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere Y8s-cc(
2、收缩数据库 @:'E9J06
--重建索引 26_PFHQu4
DBCC REINDEX `.VkR5/
DBCC INDEXDEFRAG PMQ31f/zf
--收缩数据和日志 c}=[r1M*
DBCC SHRINKDB &,XPMT
DBCC SHRINKFILE T3)m{gv0`
3、压缩数据库 zhRF>Y`
dbcc shrinkdatabase(dbname) o=2y`Eq
4、转移数据库给新用户以已存在用户权限 xS,#TU;)Ol
exec sp_change_users_login 'update_one','newname','oldname' GjA;o3(
go @M"h_Z1#
5、检查备份集 pVw)"\S%
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' Q<r O5 -K
6、修复数据库 b#.hw2?a`
ALTER DATABASE [dvbbs] SET SINGLE_USER vGC^1AM
GO #uT-_L}sw
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK $_l@k=
GO 0bpl3Fh.v
ALTER DATABASE [dvbbs] SET MULTI_USER Db=
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GO ZSMOq4Y 9
7、日志清除 %u43Pj
SET NOCOUNT ON >"S'R9t
DECLARE @LogicalFileName sysname, `{/z\
@MaxMinutes INT, fdN-Zq@'
@NewSize INT N@^?J@#V
USE tablename -- 要操作的数据库名 Z|
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SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 Ne.W-,X^cL
@MaxMinutes = 10, -- Limit on time allowed to wrap log. }yU,_:
@NewSize = 1 -- 你想设定的日志文件的大小(M) /"Om-DK%
-- Setup / initialize h8O[xca/~
DECLARE @OriginalSize int @B~/0
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SELECT @OriginalSize = size LC\Ys\/,U
FROM sysfiles |9!3{3
WHERE name = @LogicalFileName Vr f` :%
SELECT 'Original Size of ' + db_name() + ' LOG is ' + d;(L@9HHD
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + Ni{(=&*=
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' PS@`
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FROM sysfiles |]]Xee]
WHERE name = @LogicalFileName Zi2NgVF
CREATE TABLE DummyTrans C 9,p-
(DummyColumn char (8000) not null) `96:Z-!}
DECLARE @Counter INT, t4UKG&[a
@StartTime DATETIME, iR(A^
@TruncLog VARCHAR(255) $d!Sl
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SELECT @StartTime = GETDATE(), 7Z"mVh}
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' Lqbu]
DBCC SHRINKFILE (@LogicalFileName, @NewSize) W9Bl'e
EXEC (@TruncLog) n4ce)N@
-- Wrap the log if necessary. <<w $Ur
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired zpIl'/i
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 2:/'
AND (@OriginalSize * 8 /1024) > @NewSize M&y!w
BEGIN -- Outer loop. #=b_!~:%
SELECT @Counter = 0 (( Ec:(:c
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) rFn;z}J2
BEGIN -- update gV!Eotq
INSERT DummyTrans VALUES ('Fill Log') mhp5}
DELETE DummyTrans <0 R7uH
SELECT @Counter = @Counter + 1 ?'$=G4y&?
END E[6JHBE*r
EXEC (@TruncLog) /%rbXrR4w
END dt)
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + -(qoz8H5
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + b2H!{a"
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' jfS?#;T)
FROM sysfiles Y+V*$73`
WHERE name = @LogicalFileName <2ffcBv
DROP TABLE DummyTrans lyIstfRh15
SET NOCOUNT OFF _$wWKJy9
8、说明:更改某个表 i?'HVx
exec sp_changeobjectowner 'tablename','dbo' }!& w<wR
9、存储更改全部表 /^#k/z
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch E[t\LTt*n
@OldOwner as NVARCHAR(128), CjOaw$s
@NewOwner as NVARCHAR(128) B8|=P&L7N
AS o]}b#U8S
DECLARE @Name as NVARCHAR(128) pt(GpbtWK
DECLARE @Owner as NVARCHAR(128) vP3Fb;
DECLARE @OwnerName as NVARCHAR(128) <=cj)
DECLARE curObject CURSOR FOR 3>0/WbA:7E
select 'Name' = name, Xe*@`&nv@
'Owner' = user_name(uid) R?>a UFM
from sysobjects -t?S:9[w
where user_name(uid)=@OldOwner g;\zD_":l
order by name e&7GW9FSg
OPEN curObject ~VUNN[
FETCH NEXT FROM curObject INTO @Name, @Owner /!JpmI
WHILE(@@FETCH_STATUS=0) JQsS=m7Et
BEGIN o]MQ)\r
if @Owner=@OldOwner }%y_LcL
begin xh@H@Q\
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ?9v!UT
exec sp_changeobjectowner @OwnerName, @NewOwner y*\ M7}](
end h^~eTi;c]Q
-- select @name,@NewOwner,@OldOwner ~0|~Fg
FETCH NEXT FROM curObject INTO @Name, @Owner L`x:Y>C(
END _"a(vfl#
close curObject {+z+6i
deallocate curObject gO4J[_
GO X+P&
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10、SQL SERVER中直接循环写入数据 E`XUK,b
declare @i int 3l`yy])t
set @i=1 [G[HQ)A
while @i<30 b\][ x6zJp
begin _7]5Q
insert into test (userid) values(@i) E7^tU416
set @i=@i+1 ')bx1gc(?
end o&;+!Si@T
小记存储过程中经常用到的本周,本月,本年函数 {NKDmeg:D
Dateadd(wk,datediff(wk,0,getdate()),-1) y= cBpC
Dateadd(wk,datediff(wk,0,getdate()),6) ;r-
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Dateadd(mm,datediff(mm,0,getdate()),0) ]Vl*!,(i
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) %I(N
Dateadd(yy,datediff(yy,0,getdate()),0) 5p94b*l
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) *ta|,
上面的SQL代码只是一个时间段 sTeL4g|%{
Dateadd(wk,datediff(wk,0,getdate()),-1) cm-cwPAh
Dateadd(wk,datediff(wk,0,getdate()),6) Si6%6rAhj
就是表示本周时间段. -Qiay/tlu
下面的SQL的条件部分,就是查询时间段在本周范围内的: kd|@.
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) xlgN}M
而在存储过程中 &{x5 |$SD
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) #?!)-Q%
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) n|SsV