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。 n{s
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一、基础 82nQ]
1、说明:创建数据库 u]lf~EE
CREATE DATABASE database-name &^=6W3RD
2、说明:删除数据库 hX#y7m
drop database dbname \DI%/(?
3、说明:备份sql server :G=N|3
--- 创建 备份数据的 device B[%FZm $`M
USE master $p#)xx7
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 7s+3^'
--- 开始 备份 5V;BimI
BACKUP DATABASE pubs TO testBack ebxpKtEC
4、说明:创建新表 o?BcpWp
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) kq&xH;9=.
根据已有的表创建新表: 1S/KT4
A:create table tab_new like tab_old (使用旧表创建新表) `CP#S7W^
B:create table tab_new as select col1,col2... from tab_old definition only l*V]54|ON3
5、说明:删除新表 ];P$w.0
drop table tabname r`Y[XzT9
6、说明:增加一个列 ,Dd
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Alter table tabname add column col type -LI^(_
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。 P(D0ru
7、说明:添加主键: Alter table tabname add primary key(col) K: hZ
说明:删除主键: Alter table tabname drop primary key(col) b9b384Q1O
8、说明:创建索引:create [unique] index idxname on tabname(col....) lf3QMr+
删除索引:drop index idxname <Yif-9
注:索引是不可更改的,想更改必须删除重新建。 E_ #MQ;n
9、说明:创建视图:create view viewname as select statement yE1M+x./
删除视图:drop view viewname AJ1(q:P
10、说明:几个简单的基本的sql语句 0~
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选择:select * from table1 where 范围 d~n|F|`:
插入:insert into table1(field1,field2) values(value1,value2) WsO'4~X9
删除:delete from table1 where 范围 E:'TZ4Z
更新:update table1 set field1=value1 where 范围 /qM:;:N%j
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! N.R,[K
排序:select * from table1 order by field1,field2 [desc] ?"-%>y@w
总数:select count as totalcount from table1 b|F4E{{D^
求和:select sum(field1) as sumvalue from table1 U\dq
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平均:select avg(field1) as avgvalue from table1 30cZz
最大:select max(field1) as maxvalue from table1 H*s_A/$
最小:select min(field1) as minvalue from table1 TN!8J=sx.
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11、说明:几个高级查询运算词 X <QSi
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A: UNION 运算符 4B?8$&b
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。 $3.hZx>
B: EXCEPT 运算符 c%,@O&o
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 'e
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C: INTERSECT 运算符 {BB#Bh[
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 H5wzzSV!:B
注:使用运算词的几个查询结果行必须是一致的。 9HJrMX
12、说明:使用外连接 K`}8fU
A、left outer join: 36MqEUjyB
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 B q/<kEgM
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c =LLix .
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B:right outer join: E$!0h_.(
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?Fqm@J{XT
C:full outer join: $hv o^$
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。 gT3i{iU
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二、提升 /~=W3lhY
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) .%Pt[VQ
法一:select * into b from a where 1<>1 Z|l/6L8
法二:select top 0 * into b from a ^&^~LKl~
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) jNjm}8`t
insert into b(a, b, c) select d,e,f from b; KYe@2 6
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) r5#8Vzr
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 Z]VmTB
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. +bO]9*g]
4、说明:子查询(表名1:a 表名2:b)
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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) UqsJ44QEZ
5、说明:显示文章、提交人和最后回复时间 VSf<(udGr
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b Ky:y1\K1^K
6、说明:外连接查询(表名1:a 表名2:b) oXW51ty
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c uB&um*DP
7、说明:在线视图查询(表名1:a ) 4o|-v
select * from (SELECT a,b,c FROM a) T where t.a > 1; p>9-Ga
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 qpjG_G5/
select * from table1 where time between time1 and time2 QV&yVH=Xs
select a,b,c, from table1 where a not between 数值1 and 数值2 pGO=3=O
9、说明:in 的使用方法 ! J7ExfEA
select * from table1 where a [not] in ('值1','值2','值4','值6') 2^3N[pM;
10、说明:两张关联表,删除主表中已经在副表中没有的信息 L_ &`
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ^}VAH#c
11、说明:四表联查问题: jPu m2U_
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 ..... J]m[0g7O_
12、说明:日程安排提前五分钟提醒 ],.1=iY
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 DAvF ND$=
13、说明:一条sql 语句搞定数据库分页 +c&oF,=}!P
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 ?^f=7e8]
14、说明:前10条记录 gjbSB6[
select top 10 * form table1 where 范围
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15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) APR"%(xD#
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) cJ^:b4j
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 ; fOkR+
(select a from tableA ) except (select a from tableB) except (select a from tableC) *{K?JB#W
17、说明:随机取出10条数据 lPBWpHX
select top 10 * from tablename order by newid() !=/wpsH
18、说明:随机选择记录 y'{*B(
select newid() cM|!jnKm
19、说明:删除重复记录 39!$x[
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) ;5cN
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20、说明:列出数据库里所有的表名 ZUg~8VVe
select name from sysobjects where type='U' Q)lN7oD
21、说明:列出表里的所有的 )0\"8}!
select name from syscolumns where id=object_id('TableName') |``rSEXYs
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。 .5s#JL
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 gS
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显示结果: 78u9> H
type vender pcs *i`t4N
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电脑 A 1 }HLs.k4-;
电脑 A 1 $F#eD0|
光盘 B 2 zxD~W"R:s
光盘 A 2 X"sc'#G T
手机 B 3 9P7^*f:E
手机 C 3 C2a2K={
23、说明:初始化表table1 c04;2gR
TRUNCATE TABLE table1 (gQr?K
24、说明:选择从10到15的记录 $yoIz.?V
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc &%=]lP]
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三、技巧 Md5|j0#p
1、1=1,1=2的使用,在SQL语句组合时用的较多 n)bbEXO
"where 1=1" 是表示选择全部 "where 1=2"全部不选, pPD}>q
如: pl4:>4l/
if @strWhere !='' Tu[I84
begin k
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ~!iZn
end b;2[E/JKB
else j7>a^W
begin s9\N{ar#
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' +N>z|T<
end Ij{ K\{y
我们可以直接写成 x^XP<R{D
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 04E
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2、收缩数据库 AK_,$'f
--重建索引 \&,{N_G#L.
DBCC REINDEX yBYZ? gc
DBCC INDEXDEFRAG K2@],E?e%|
--收缩数据和日志 a)qlrtCl
DBCC SHRINKDB ,T;T%/
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DBCC SHRINKFILE mJYG k_ua
3、压缩数据库 "IA:,j.#g
dbcc shrinkdatabase(dbname) tm|YUat$]r
4、转移数据库给新用户以已存在用户权限 :={rPj-nU
exec sp_change_users_login 'update_one','newname','oldname' 6-t:eo9
go 3jzmiS]
5、检查备份集 ClWxL#L6~
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' gnWEsA\!
6、修复数据库 3[cGSI"+
ALTER DATABASE [dvbbs] SET SINGLE_USER KGP *G
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GO qo!6)Z
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ^$x1~}D
GO ur|
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ALTER DATABASE [dvbbs] SET MULTI_USER 3'xmq
GO [;LP6n7v
7、日志清除 Lz:Q6
SET NOCOUNT ON N;|:Ks#!
DECLARE @LogicalFileName sysname, kVY0
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@MaxMinutes INT, *Kmo1>^
@NewSize INT tpj6AMO/`d
USE tablename -- 要操作的数据库名 `s|^
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ~(P\'H&(h
@MaxMinutes = 10, -- Limit on time allowed to wrap log. \]Y=*+{
@NewSize = 1 -- 你想设定的日志文件的大小(M) pp1kcrE\M
-- Setup / initialize \}EJtux q
DECLARE @OriginalSize int q!Q*T^-rO
SELECT @OriginalSize = size .:9XpKbt
FROM sysfiles xDO1gnH%
WHERE name = @LogicalFileName Prqr,
SELECT 'Original Size of ' + db_name() + ' LOG is ' + u_'XUJ32!
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + |576)
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' {D`_q|
FROM sysfiles s#4Q?<65u
WHERE name = @LogicalFileName %j.
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CREATE TABLE DummyTrans #QM9!k@9k
(DummyColumn char (8000) not null) qE@H~&
DECLARE @Counter INT, #``Alh8
@StartTime DATETIME, ::k
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@TruncLog VARCHAR(255) y*vg9`$k
SELECT @StartTime = GETDATE(), Y5R|)x
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ]\6*2E{1m
DBCC SHRINKFILE (@LogicalFileName, @NewSize) /:+MUw7~
EXEC (@TruncLog) z"$huE>P6
-- Wrap the log if necessary. n,*E
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WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired Z11I1)%s
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) Nc\jA=
AND (@OriginalSize * 8 /1024) > @NewSize <Url&Z
BEGIN -- Outer loop. }S=m :
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SELECT @Counter = 0 ot;
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WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) SS7C|*-Zd
BEGIN -- update $m[*)0/
INSERT DummyTrans VALUES ('Fill Log') UYkuz
DELETE DummyTrans U`kO<ztk
SELECT @Counter = @Counter + 1 gI{56Z
END Ur,{ZGm
EXEC (@TruncLog) "VI2--%v3
END p.RSH$]
SELECT 'Final Size of ' + db_name() + ' LOG is ' + aSH =|Jnc
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 6>F1!Q
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' miEf<<L#z
FROM sysfiles 3bZ:*6W.6
WHERE name = @LogicalFileName >fx/TSql:J
DROP TABLE DummyTrans !+Zso&
SET NOCOUNT OFF t`G<}t
8、说明:更改某个表 M <ccfU!
exec sp_changeobjectowner 'tablename','dbo' ?V$@2vBVX4
9、存储更改全部表 ,'a[1RN
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 22gh,e2o
@OldOwner as NVARCHAR(128), tr$d?
@NewOwner as NVARCHAR(128) 9YVr9BM'K
AS Cg&:+
DECLARE @Name as NVARCHAR(128) )@E'yHYO>
DECLARE @Owner as NVARCHAR(128) ~NZ}@J{00_
DECLARE @OwnerName as NVARCHAR(128) KYC<*1k
DECLARE curObject CURSOR FOR =0mXTY1
select 'Name' = name, )(W%Hmi
'Owner' = user_name(uid) R:Tv'I1-L
from sysobjects n$E'+kox
where user_name(uid)=@OldOwner 17S<6j#H5
order by name ?X3uPj9if
OPEN curObject (F'?c1
FETCH NEXT FROM curObject INTO @Name, @Owner `(VVb@:o
WHILE(@@FETCH_STATUS=0)
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BEGIN cW?~]E'<
if @Owner=@OldOwner x_OZdI
begin )!g@MHHL
set @OwnerName = @OldOwner + '.' + rtrim(@Name) of0hJR
exec sp_changeobjectowner @OwnerName, @NewOwner ldNWdz
end ;`rz ]7,*
-- select @name,@NewOwner,@OldOwner G ;
FETCH NEXT FROM curObject INTO @Name, @Owner .7r$jmuFs
END uV\~2#o$_
close curObject P;[>TCs ]8
deallocate curObject 'OvyQ/T
GO e\WG-zi/
10、SQL SERVER中直接循环写入数据 KK41I8Mw
declare @i int L]QBh\
set @i=1 -14~f)%NQ*
while @i<30 mmBZ}V+&=
begin 0JX/@LNg0
insert into test (userid) values(@i) u!9bhL`
set @i=@i+1 7^n{BsN
end -A)/CFIZ
小记存储过程中经常用到的本周,本月,本年函数 qY|NA)E)Bp
Dateadd(wk,datediff(wk,0,getdate()),-1) "<1-9CMl
Dateadd(wk,datediff(wk,0,getdate()),6) Vo(V<2lw}
Dateadd(mm,datediff(mm,0,getdate()),0) _NB8>v
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) U?(+ {4l
Dateadd(yy,datediff(yy,0,getdate()),0) $S2kc$'F
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) h f9yK6
上面的SQL代码只是一个时间段 [*v-i%U}
Dateadd(wk,datediff(wk,0,getdate()),-1) S<nbNSu6+
Dateadd(wk,datediff(wk,0,getdate()),6) g33Y]\
就是表示本周时间段. ^ Mw=!n[
下面的SQL的条件部分,就是查询时间段在本周范围内的: @W\H%VR
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) CpdQ]Ai[
而在存储过程中 fhbILg
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) '^~38=FA
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) m_,j)A%