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。 4
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一、基础 \(2sW^fY
1、说明:创建数据库 sD#.Oq4&]y
CREATE DATABASE database-name .U]-j\
2、说明:删除数据库 40m -ch6Q
drop database dbname ^Xh^xL2cn
3、说明:备份sql server -PR N:'T
--- 创建 备份数据的 device w ;^ra<*<+
USE master ^^D0^k!R
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' sLxc(d'A
--- 开始 备份 o|["SYIf
BACKUP DATABASE pubs TO testBack A^<jy=F&
4、说明:创建新表 |aq"#Ml)
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) JDT`C2-Q
根据已有的表创建新表: HLG"a3tt
A:create table tab_new like tab_old (使用旧表创建新表) 61'XgkacDS
B:create table tab_new as select col1,col2... from tab_old definition only 8FY?!C
5、说明:删除新表 7J<5f)
drop table tabname -e:`|(Mo
6、说明:增加一个列 P\k# >}}
Alter table tabname add column col type &^Q/,H~S
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。 c\AfaK^KF
7、说明:添加主键: Alter table tabname add primary key(col) ;u)I\3`*!
说明:删除主键: Alter table tabname drop primary key(col) 1bX<$>x9u
8、说明:创建索引:create [unique] index idxname on tabname(col....) SO0PF|{\r
删除索引:drop index idxname [` 7ThHX
注:索引是不可更改的,想更改必须删除重新建。 20Wg=p9L
9、说明:创建视图:create view viewname as select statement cyz3,3\e
删除视图:drop view viewname wI/iuc
10、说明:几个简单的基本的sql语句 F7#JLE=
选择:select * from table1 where 范围 H9e<v4c
插入:insert into table1(field1,field2) values(value1,value2) {R6ZKB
删除:delete from table1 where 范围 $6SW;d+>n
更新:update table1 set field1=value1 where 范围 <7jW_R@
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 8bld3p"^
排序:select * from table1 order by field1,field2 [desc] ~b8]H|<'Y
总数:select count as totalcount from table1 P/_['7
求和:select sum(field1) as sumvalue from table1 9 djk[ttA)
平均:select avg(field1) as avgvalue from table1 -(H0>Ap
最大:select max(field1) as maxvalue from table1 %1+4_g9
最小:select min(field1) as minvalue from table1 (SAs-
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11、说明:几个高级查询运算词 <wD-qT W
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A: UNION 运算符 )lDD\J7
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。 IjnU?Bf
B: EXCEPT 运算符 d/~9&wLSb
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。
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C: INTERSECT 运算符 8KzkB;=n
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。 13x p_j
注:使用运算词的几个查询结果行必须是一致的。 L.JT[zOfb
12、说明:使用外连接 j1T#yt
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A、left outer join: 1bwOmhkS
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。 ^^ixa1H<
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 CRy|kkT
B:right outer join: j?4qO]_Wx+
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。 5`p.#
C:full outer join: uoh7Sz5!^
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。 ;9QEK]@
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二、提升 uQKT
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) YPI-<vM~
法一:select * into b from a where 1<>1 KoT%Mfu
法二:select top 0 * into b from a FfT`;j
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) Wmv#:U
insert into b(a, b, c) select d,e,f from b; 88$8d>-
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) f]srRYSR
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 Uw<nxD/+
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. U| R_OLWAg
4、说明:子查询(表名1:a 表名2:b) dG ?*y
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) ]3Sp W{=^(
5、说明:显示文章、提交人和最后回复时间 7WzxA=*#
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b )zDCu`
6、说明:外连接查询(表名1:a 表名2:b) /Lr.e%
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c +9sQZB# (
7、说明:在线视图查询(表名1:a ) [j+sC*
select * from (SELECT a,b,c FROM a) T where t.a > 1; U 8$27jq
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 sc#qwQ#
select * from table1 where time between time1 and time2 (X*^dO
select a,b,c, from table1 where a not between 数值1 and 数值2 1T
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9、说明:in 的使用方法 ?(_08O
select * from table1 where a [not] in ('值1','值2','值4','值6') 'PW5ux@`<
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ")p\q:z6
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Z6MO^_m2
11、说明:四表联查问题: !0<,@v"
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 ..... 44j*KsBf
12、说明:日程安排提前五分钟提醒 SiN0OB
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ]u/sphPe
13、说明:一条sql 语句搞定数据库分页 b^vQpiz
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 )Hr`MB
14、说明:前10条记录 YKK*ER0
select top 10 * form table1 where 范围 XfIJ4ZM5
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.) 2=!RQv~%
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) Y"$xX8o
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 uHRsFlw
(select a from tableA ) except (select a from tableB) except (select a from tableC) !&@615Vtw
17、说明:随机取出10条数据 4 s9LB
select top 10 * from tablename order by newid() - " 9
18、说明:随机选择记录 ;*2Cm'8E
select newid() }4X0epPp;:
19、说明:删除重复记录 ]7c=PC
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) R`-S/C
20、说明:列出数据库里所有的表名 AbW6x
select name from sysobjects where type='U' +R75v )
21、说明:列出表里的所有的 #}5uno
select name from syscolumns where id=object_id('TableName') FW DNpr
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。 }"%N4(Kd
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 * kh tJ]=
显示结果: _
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type vender pcs P@~yx#G
电脑 A 1 7tCw*t$
电脑 A 1 goWuw}?
光盘 B 2 \cM2k-
光盘 A 2 HTTCTR
手机 B 3 %
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手机 C 3 `){.+S(5C
23、说明:初始化表table1 :\_ 5oVb
TRUNCATE TABLE table1 Qn2&nD%zi
24、说明:选择从10到15的记录 buHJB*?9
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc \a3+rNdj
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三、技巧 V>3X\)qu
1、1=1,1=2的使用,在SQL语句组合时用的较多 *|HY>U.
"where 1=1" 是表示选择全部 "where 1=2"全部不选, )0k53-h&
如:
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if @strWhere !='' E=O\0!F|b
begin J]r^W)O
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere bpa?C
end <(! :$
else |k00Z+O(
begin z\4.Gm-
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ;q>ah!"k
end o^wqFX(Y
我们可以直接写成 tfWS)y7
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere %\:Wi#w>
2、收缩数据库 .x&%HA
--重建索引 u)Whr@m
DBCC REINDEX 8H`[*|{'
DBCC INDEXDEFRAG ;<4a*;IO
--收缩数据和日志 &BSn?
DBCC SHRINKDB iH'p>s5L
DBCC SHRINKFILE hgE71H\s
3、压缩数据库 AbOf6%Env
dbcc shrinkdatabase(dbname) RPbZ(.
4、转移数据库给新用户以已存在用户权限 +aAc9'k
exec sp_change_users_login 'update_one','newname','oldname' I5W~g.<6
go 0<*<$U
5、检查备份集 Vi|#@tC'
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ?Z} &EH
6、修复数据库 tpx2IE
ALTER DATABASE [dvbbs] SET SINGLE_USER HjwE+: w
GO b7ZSPXV
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK NwfVL4Xg
GO sa8Vvzvo.
ALTER DATABASE [dvbbs] SET MULTI_USER PQE=D0
GO DVeE1Q
7、日志清除 A]3k4DLYS
SET NOCOUNT ON \GU<43J2uo
DECLARE @LogicalFileName sysname, b\5F ]r
@MaxMinutes INT, !bP@n
@NewSize INT
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USE tablename -- 要操作的数据库名 V28M lP
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 yIE!j%u
@MaxMinutes = 10, -- Limit on time allowed to wrap log. z0Z%m@
@NewSize = 1 -- 你想设定的日志文件的大小(M) 7-V/RChBm
-- Setup / initialize !p/goqT~dY
DECLARE @OriginalSize int 0tJZ4(0
SELECT @OriginalSize = size tT._VK]o&R
FROM sysfiles BFt> 9x]T
WHERE name = @LogicalFileName o#N+Y?O
SELECT 'Original Size of ' + db_name() + ' LOG is ' + c+GG\:gM
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 6wg^FD_Q
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' EhBKj |y
FROM sysfiles rSNi@;
WHERE name = @LogicalFileName c[s4EUG
CREATE TABLE DummyTrans (w zQ2Dk
(DummyColumn char (8000) not null) ?r!o~|9|
DECLARE @Counter INT, {\\Tgs
@StartTime DATETIME, U%/+B]6jP
@TruncLog VARCHAR(255) -ze J#B)C
SELECT @StartTime = GETDATE(), 2+WaA,
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' H6gSO(U
DBCC SHRINKFILE (@LogicalFileName, @NewSize) &,)&%Sg[
EXEC (@TruncLog) A/?7w
-- Wrap the log if necessary. c4z R*
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired VS|2|n1<6
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) DIUjn;>k8
AND (@OriginalSize * 8 /1024) > @NewSize 7mfS*aCb
BEGIN -- Outer loop. :MDKC /mC
SELECT @Counter = 0 @KUWxFak
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) /<BI46B\
BEGIN -- update `QY)!$mUIF
INSERT DummyTrans VALUES ('Fill Log') ;GD]dW#
DELETE DummyTrans 8JUwf
SELECT @Counter = @Counter + 1 4`=mu}Y2
END `qwBn=
EXEC (@TruncLog) +W+|%qM,\
END D3K8F@d
SELECT 'Final Size of ' + db_name() + ' LOG is ' + <\S:'g"(
CONVERT(VARCHAR(30),size) + ' 8K pages or ' +
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CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' k|f4Cf,
FROM sysfiles %N_%JK\{@
WHERE name = @LogicalFileName {f p[BF
DROP TABLE DummyTrans ^dxTm1Z
SET NOCOUNT OFF Wn}'bqp
8、说明:更改某个表 xe$_aBU
exec sp_changeobjectowner 'tablename','dbo' ,"0:3+(8;
9、存储更改全部表 Q=dy<kg']
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch S5EK~#-L[
@OldOwner as NVARCHAR(128), ?Ss!e$jf
@NewOwner as NVARCHAR(128) ]J]h#ZHx
AS PmM3]xVzd
DECLARE @Name as NVARCHAR(128) 2b8L\$1q
DECLARE @Owner as NVARCHAR(128) Jfl!#UAD|n
DECLARE @OwnerName as NVARCHAR(128) +qdEq_m
DECLARE curObject CURSOR FOR <=C?e<Y
select 'Name' = name, @=f\<"$vt
'Owner' = user_name(uid) 3irl
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from sysobjects '/%H3A#L
where user_name(uid)=@OldOwner H" 7u7l
order by name =H]@n|$(
OPEN curObject 2I{"XB
FETCH NEXT FROM curObject INTO @Name, @Owner Oa>Ppldeg
WHILE(@@FETCH_STATUS=0) mB)bcuPv
BEGIN 1m0c|ckb
if @Owner=@OldOwner ygl0k \
begin dUdT7ixo
set @OwnerName = @OldOwner + '.' + rtrim(@Name) T&7qC=E#5
exec sp_changeobjectowner @OwnerName, @NewOwner zp?`N;
end 11;zNjD|
-- select @name,@NewOwner,@OldOwner @`Su0W+.
FETCH NEXT FROM curObject INTO @Name, @Owner r#mx~OVkk
END -`6+UkOV[x
close curObject +x}<IS8
deallocate curObject Fv`,3aNB
GO 6;5Ss?ep
10、SQL SERVER中直接循环写入数据 Ilm^G}GB
declare @i int Rbv;?'O$L
set @i=1 ;YL i{
while @i<30 ?!/kZM_ts
begin %vi83%$'4
insert into test (userid) values(@i) seeBS/%
set @i=@i+1 El"Q'(:/U
end {H'Y `+
小记存储过程中经常用到的本周,本月,本年函数 o*hF<D$Y
Dateadd(wk,datediff(wk,0,getdate()),-1) FHI ;)wn=
Dateadd(wk,datediff(wk,0,getdate()),6) ENY+^7
Dateadd(mm,datediff(mm,0,getdate()),0) cj5+NM"
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 3"\l u?-E
Dateadd(yy,datediff(yy,0,getdate()),0) Dv`c<+q(#
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) \xoP)Ub>
上面的SQL代码只是一个时间段 u\nh[1)a)
Dateadd(wk,datediff(wk,0,getdate()),-1)
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Dateadd(wk,datediff(wk,0,getdate()),6) RViuJ;
就是表示本周时间段. }*"p?L^p{
下面的SQL的条件部分,就是查询时间段在本周范围内的: Kx JqbLUC
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) %H"47ZFxAs
而在存储过程中 uY'HT|@:{
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 7. ;3e@s
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) y"wShAR