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。 >o"3:/3
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一、基础 Fl^}tC
1、说明:创建数据库 Y8yRQz u
CREATE DATABASE database-name 4? a!6
2、说明:删除数据库 2!^[x~t
drop database dbname `X7ns?
3、说明:备份sql server M1f^Lx
--- 创建 备份数据的 device StuDtY
USE master \PB ~6
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 044*@a5f
--- 开始 备份 [ZP8[Zl'?
BACKUP DATABASE pubs TO testBack zu
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4、说明:创建新表 `+(|$?C u
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) GL_a`.=@
根据已有的表创建新表: .h8%zB#|i
A:create table tab_new like tab_old (使用旧表创建新表) uoe5@j2
B:create table tab_new as select col1,col2... from tab_old definition only JyX7I,0
5、说明:删除新表 >r"~t70C~]
drop table tabname }Rc8\,
6、说明:增加一个列 SEc3`y;j%
Alter table tabname add column col type fYzOT,c
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。 yEfV8aY'*
7、说明:添加主键: Alter table tabname add primary key(col) |,ZmRW^2K
说明:删除主键: Alter table tabname drop primary key(col) {m/\AG)1I
8、说明:创建索引:create [unique] index idxname on tabname(col....) hL,+wJ+A
删除索引:drop index idxname D~xUr)E
注:索引是不可更改的,想更改必须删除重新建。 *QF3l0&
9、说明:创建视图:create view viewname as select statement <k^P>Irb3t
删除视图:drop view viewname $MmCh&V
10、说明:几个简单的基本的sql语句 .qioEqK8!y
选择:select * from table1 where 范围 ReCmv/AE
插入:insert into table1(field1,field2) values(value1,value2) d&p]O
删除:delete from table1 where 范围 aO]0|<2
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更新:update table1 set field1=value1 where 范围 kxg]sr"
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! '`Smg3T!~S
排序:select * from table1 order by field1,field2 [desc] {t$
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总数:select count as totalcount from table1 Odr@9MJ
求和:select sum(field1) as sumvalue from table1 Upr:sB
平均:select avg(field1) as avgvalue from table1 `1NxS35u
最大:select max(field1) as maxvalue from table1 :I5]|pt
最小:select min(field1) as minvalue from table1 OT9\K_
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11、说明:几个高级查询运算词 [Pdm1]":(
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A: UNION 运算符 26E"Ui5q
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。 .d5|Fs~B
B: EXCEPT 运算符 gno V>ON0
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。 W.ud<OKP90
C: INTERSECT 运算符 b\%=mN
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。 OH28H),}
注:使用运算词的几个查询结果行必须是一致的。 &DFe+y~PR
12、说明:使用外连接 $;_'5`xs
A、left outer join: ,$habq=;
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。 m%$z&<!
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c l|ZwZix
B:right outer join: cK>5!2b
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 NBR6$n
C:full outer join: 7;C9V`
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。 \>j._# t$h
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二、提升 ctOC.
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) !UD62yw~
法一:select * into b from a where 1<>1 zVs_|x="
法二:select top 0 * into b from a Hi{c[;
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) "RH2%
insert into b(a, b, c) select d,e,f from b; _VR Sdr5
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) !GMb~
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 n]x4twZ
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. JBa=R^k
4、说明:子查询(表名1:a 表名2:b) YizJT0$
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) 9o P8| <+
5、说明:显示文章、提交人和最后回复时间 J?-"]s`J
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b F]W'spF,
6、说明:外连接查询(表名1:a 表名2:b) YF@'t~_Z
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c !>/U6h,_
7、说明:在线视图查询(表名1:a ) i6r%;ueLb
select * from (SELECT a,b,c FROM a) T where t.a > 1; Xt/T0.I
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 :>'^l?b'WX
select * from table1 where time between time1 and time2 w&v_#\T
select a,b,c, from table1 where a not between 数值1 and 数值2 3skq%;%Wsk
9、说明:in 的使用方法 BpCzmU
select * from table1 where a [not] in ('值1','值2','值4','值6') PDX^MYoN
10、说明:两张关联表,删除主表中已经在副表中没有的信息 .*D~ .!
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) E/ (:\Cm^
11、说明:四表联查问题: /Z>#lMg\.
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 ..... :9c
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12、说明:日程安排提前五分钟提醒 KEsMes(*
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ~,Q+E8
13、说明:一条sql 语句搞定数据库分页 _U$d.B'*)z
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 !O)Ruwy
14、说明:前10条记录 pq>"GEN
select top 10 * form table1 where 范围 anA>' 63
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) -zHJ#
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) GS~jNZx
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 %Md;=,a:6
(select a from tableA ) except (select a from tableB) except (select a from tableC) Cdiu*#f
17、说明:随机取出10条数据 Te2XQU2,F
select top 10 * from tablename order by newid() ZSYXUFz
18、说明:随机选择记录 c3!d4mC:
select newid() g`gH]W
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19、说明:删除重复记录 suaTXKjyk+
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) W*-+j*e|_P
20、说明:列出数据库里所有的表名 _=j0Y=/IF
select name from sysobjects where type='U' bR49(K$~
21、说明:列出表里的所有的 ^Ebaq`{V\'
select name from syscolumns where id=object_id('TableName') x!MYIaZ7
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。 of8/~VO
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 UBi0
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显示结果: +|Xx=1_?BK
type vender pcs %`HAg MgP
电脑 A 1 }9>W41
电脑 A 1 9pStArF?F0
光盘 B 2 =4/lJm``
光盘 A 2 I9ubV cV8
手机 B 3 >! wX%QHH
手机 C 3 &K)c*'l
23、说明:初始化表table1 {Rjj
TRUNCATE TABLE table1 s{KwO+ UW
24、说明:选择从10到15的记录
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select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 4'?kyTO~
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三、技巧 D>~z{H%\
1、1=1,1=2的使用,在SQL语句组合时用的较多 4&r^mGs,
"where 1=1" 是表示选择全部 "where 1=2"全部不选, o{?s\)aBa
如: DK&J"0jz,
if @strWhere !='' LnxJFc:1K
begin Wze\z
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere CP'?Om2
end %z tCcgu*
else JpD<2Mz_|V
begin lzfaW-nu
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' zOCru2/
end -JaC~v(0
我们可以直接写成 tV@!jaj\
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 7
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2、收缩数据库 7:R8QS9
--重建索引 yiSv#wD9
DBCC REINDEX <:2El9l!
DBCC INDEXDEFRAG $dgY#ST%
--收缩数据和日志 'F?T4
DBCC SHRINKDB t@>Uc`%
DBCC SHRINKFILE /'u-Fr(Q+
3、压缩数据库 W'-B)li
dbcc shrinkdatabase(dbname) SI*O#K=w
4、转移数据库给新用户以已存在用户权限 <E|i3\[p
exec sp_change_users_login 'update_one','newname','oldname' :o&qJ%
go uYhm
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5、检查备份集 {XC# -3O
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' SQ]&nDd
6、修复数据库 ^|Of
ALTER DATABASE [dvbbs] SET SINGLE_USER |(*ReQ?=
GO 5<GC
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK =" #O1$
GO V"#ie
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ALTER DATABASE [dvbbs] SET MULTI_USER tVvRT*>Wb
GO g599Lc&
7、日志清除 PiMh]
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SET NOCOUNT ON #Fl"#g$
DECLARE @LogicalFileName sysname, H@qA X
@MaxMinutes INT, sikG}p0mx<
@NewSize INT =m:xf&r#
USE tablename -- 要操作的数据库名 B5~S&HQ?B6
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ^9%G7J:vGO
@MaxMinutes = 10, -- Limit on time allowed to wrap log. tz)aQ6p\X
@NewSize = 1 -- 你想设定的日志文件的大小(M) D4ESo)15'
-- Setup / initialize p}.L]Y
DECLARE @OriginalSize int ZC@ 33Q(
SELECT @OriginalSize = size y-)|u:~h
FROM sysfiles &{]zL
WHERE name = @LogicalFileName (q59cA w~X
SELECT 'Original Size of ' + db_name() + ' LOG is ' + f6j;Y<}' g
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + >_jT.d
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' ?"N,do
FROM sysfiles btJ:Wt}
WHERE name = @LogicalFileName $5jQm,V$K
CREATE TABLE DummyTrans X&8&NkH
(DummyColumn char (8000) not null) oa? bOm
DECLARE @Counter INT, G<# 9`
@StartTime DATETIME, }Ry:})
@TruncLog VARCHAR(255) S4aN7.'Q
SELECT @StartTime = GETDATE(), 7;jwKA;k
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' Kp'_lKW)]q
DBCC SHRINKFILE (@LogicalFileName, @NewSize) lRF04
EXEC (@TruncLog) <La$'lG4J
-- Wrap the log if necessary. -hiG8%l5
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired SpU+y|\[0
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) O; 7`*}m
AND (@OriginalSize * 8 /1024) > @NewSize ?{NP3
BEGIN -- Outer loop. zt/b S/
SELECT @Counter = 0 ?'Y\5n/*$
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) Ly"u }e
BEGIN -- update 6oMU) DIa
INSERT DummyTrans VALUES ('Fill Log') SMY,bU'a
DELETE DummyTrans oDogM`T`
SELECT @Counter = @Counter + 1 26.),a
END \1cay#X
EXEC (@TruncLog) NGcd
END SU~t7Ta!G
SELECT 'Final Size of ' + db_name() + ' LOG is ' + P$ZIKkf
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + l=ehoyER
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ~[l6;bn
FROM sysfiles fb3(9
WHERE name = @LogicalFileName 6c,]N@,Zw
DROP TABLE DummyTrans 0+L:+S
SET NOCOUNT OFF
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8、说明:更改某个表 {4J:t_<nKO
exec sp_changeobjectowner 'tablename','dbo' zP$0B!9
9、存储更改全部表 1O]'iS"
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch epuN~T
@OldOwner as NVARCHAR(128), >?aPXC
@NewOwner as NVARCHAR(128) {AUhF}O
AS mSF>~D1_
DECLARE @Name as NVARCHAR(128) Sio^FOTD
DECLARE @Owner as NVARCHAR(128) 0tyoH3o/d
DECLARE @OwnerName as NVARCHAR(128) ?f f !(U
DECLARE curObject CURSOR FOR X |zQZ<CO
select 'Name' = name, Hof@,w
'Owner' = user_name(uid) meey5}
from sysobjects )c!7V)z
where user_name(uid)=@OldOwner "HX,RJ
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order by name qM=
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OPEN curObject y (@j;Q3(r
FETCH NEXT FROM curObject INTO @Name, @Owner 7DZxrVw
WHILE(@@FETCH_STATUS=0) .<7M4Z
BEGIN @SeInew;`l
if @Owner=@OldOwner tIn
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begin B( r~Nvc
set @OwnerName = @OldOwner + '.' + rtrim(@Name) go >*n\
exec sp_changeobjectowner @OwnerName, @NewOwner 9'nM$a
end N3dS%F,_
-- select @name,@NewOwner,@OldOwner 2[!#Xf
FETCH NEXT FROM curObject INTO @Name, @Owner hEUS&`K
END Z>hS&B
close curObject :/UO3 c(
deallocate curObject ko<u0SjF)u
GO 9Rl-Jz8g
10、SQL SERVER中直接循环写入数据 B=14
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declare @i int omz%:'m`~
set @i=1 j3>0oe!
while @i<30 DQ%bcXs
begin [hzw..?g
insert into test (userid) values(@i) 7QV@lR<C2R
set @i=@i+1 )aSj!X'`;
end .)=T1^[hI
小记存储过程中经常用到的本周,本月,本年函数 E)w6ZwV
Dateadd(wk,datediff(wk,0,getdate()),-1) &U*MLf83`
Dateadd(wk,datediff(wk,0,getdate()),6) &!i'Q;q
Dateadd(mm,datediff(mm,0,getdate()),0) [bM$n
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Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) cxX/ b,
Dateadd(yy,datediff(yy,0,getdate()),0) )gF>nNE
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) h,-2+}
上面的SQL代码只是一个时间段 8xf]zM"Q
Dateadd(wk,datediff(wk,0,getdate()),-1) YX*NjXL
Dateadd(wk,datediff(wk,0,getdate()),6) 2L!s'^m-
就是表示本周时间段. Ao?y2 [sE
下面的SQL的条件部分,就是查询时间段在本周范围内的: QFekj@
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ox:m;-Ml?_
而在存储过程中 pHKcKqB*13
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) HGycF|]2
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) rtM29~c>@