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。 KT?s\w
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一、基础 ~
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1、说明:创建数据库 bg. KkJMrR
CREATE DATABASE database-name QI{Y@xQ
2、说明:删除数据库 ! \Kh\
drop database dbname J4^cd
3、说明:备份sql server !@ '2
--- 创建 备份数据的 device [uV/ Ra*g
USE master } dlNMW
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ?uBC{KQ}Y
--- 开始 备份 /Bu5kBC
BACKUP DATABASE pubs TO testBack d> AmM!J
4、说明:创建新表 iR =aYT~
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ~ZC=!|Q#
根据已有的表创建新表: N4NH)x
A:create table tab_new like tab_old (使用旧表创建新表) <b40\Z{+
B:create table tab_new as select col1,col2... from tab_old definition only VqU:`?#"a
5、说明:删除新表 fJV VW
drop table tabname u^[v{hv'H
6、说明:增加一个列 a'~y'6
Alter table tabname add column col type :!\./z8v
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。 'gH#\he[Dh
7、说明:添加主键: Alter table tabname add primary key(col) $B/cj^3
说明:删除主键: Alter table tabname drop primary key(col) e28#Yh@U
8、说明:创建索引:create [unique] index idxname on tabname(col....) RuuU}XQ
删除索引:drop index idxname wfzb:Aig`
注:索引是不可更改的,想更改必须删除重新建。 ]<= t
9、说明:创建视图:create view viewname as select statement sVnuSm
删除视图:drop view viewname # nhAW
10、说明:几个简单的基本的sql语句 ^;_b!7*
选择:select * from table1 where 范围 o%5Ao?z~
插入:insert into table1(field1,field2) values(value1,value2) <K'gvMG[
删除:delete from table1 where 范围 (#Aq*2Z.
更新:update table1 set field1=value1 where 范围 ;OyM~T gI
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! S5!2%-;<k
排序:select * from table1 order by field1,field2 [desc] V>SA3
总数:select count as totalcount from table1 tB7aHZ|
求和:select sum(field1) as sumvalue from table1 [J3;U6
平均:select avg(field1) as avgvalue from table1 =@MKU
最大:select max(field1) as maxvalue from table1 ?xs0J
最小:select min(field1) as minvalue from table1 !*-cf$
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11、说明:几个高级查询运算词 _m-r}9au
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A: UNION 运算符 M
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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。 \/Y<.#?_
B: EXCEPT 运算符 ,{at?y*
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。 jd*H$BU^
C: INTERSECT 运算符 i[n1}E.@
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。 S3fBZIPp
注:使用运算词的几个查询结果行必须是一致的。 /#5ZP\e
12、说明:使用外连接 JN!YRcj
A、left outer join: Bnv%W4
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。 R4;6Oi)
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 lHXH03
B:right outer join: zYsGI<4
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。 q[ZYlF,Ho
C:full outer join: }J`Gm
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!rz@Y3
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二、提升 \266N;JrN
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) #>'0C6Xn
法一:select * into b from a where 1<>1 /-lmfpT
法二:select top 0 * into b from a 2F(j=uV+
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) v/dcb%
insert into b(a, b, c) select d,e,f from b; *<1m
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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) UHWunI S
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 d8 po`J#nb
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ZW"J]"A
4、说明:子查询(表名1:a 表名2:b) $mlcaH
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) #'P&L>6
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5、说明:显示文章、提交人和最后回复时间 &s5*akG
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b Y*f<\z(4
6、说明:外连接查询(表名1:a 表名2:b) LTHS&3%2
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c S;~_9i]upe
7、说明:在线视图查询(表名1:a ) F(r&:3!97
select * from (SELECT a,b,c FROM a) T where t.a > 1; C&gJP7 UF
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 XJ+sm^`vOf
select * from table1 where time between time1 and time2 9q?gmAn.
select a,b,c, from table1 where a not between 数值1 and 数值2 }$ der
9、说明:in 的使用方法 7=9jXNk Y
select * from table1 where a [not] in ('值1','值2','值4','值6') ]g :ZokU
10、说明:两张关联表,删除主表中已经在副表中没有的信息 uwJkqlUOz
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 1+'3{m \5T
11、说明:四表联查问题: +zvK/Fj2q
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 ..... z,WrLZC
12、说明:日程安排提前五分钟提醒 paY%pU
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 @z.!Dby
13、说明:一条sql 语句搞定数据库分页 t{9Ph]e
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 r%4:,{HF
14、说明:前10条记录 dhbJ1/z^
select top 10 * form table1 where 范围 ux=@"!PJ
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.) S{ !hpq~o
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) (TPD!=
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 Bb)J8,LQ
(select a from tableA ) except (select a from tableB) except (select a from tableC) w&H7S{
17、说明:随机取出10条数据 ,ic}
select top 10 * from tablename order by newid() 7VraWW`H'
18、说明:随机选择记录 V#gXchH[L
select newid() xS'So7: h
19、说明:删除重复记录 [Pay<]c6g
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) =*pu+o,?
20、说明:列出数据库里所有的表名 n~Ix8|S h
select name from sysobjects where type='U' ^]HwStn&=
21、说明:列出表里的所有的 u|E,Wy1
select name from syscolumns where id=object_id('TableName') d hy= x
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。 +;T%7j"wz
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 Z:}^fZP
显示结果: 4(NI-|q0
type vender pcs yd k
电脑 A 1 @gd-lcMYW
电脑 A 1 4'M#m|V
光盘 B 2 A<&9
光盘 A 2 HDYf^mcW
手机 B 3 kI]1J
手机 C 3 w[XW>4xK
23、说明:初始化表table1 <7XdT
TRUNCATE TABLE table1 b\?`721BG
24、说明:选择从10到15的记录 .*,ZcO
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc 8cHZBM7'
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三、技巧 LxbVRw
1、1=1,1=2的使用,在SQL语句组合时用的较多 =o {`vv
"where 1=1" 是表示选择全部 "where 1=2"全部不选, j>U.(K
如: C/XOI>
if @strWhere !='' pT
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begin <NUZPX29
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere cWi2Sls
end mEA w^
else uQDu<@5^[
begin NJ~'`{3v
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' WJ%b9{<
end R$\ieNb
我们可以直接写成 ^m~=<4eX
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere C]k\GlhB
2、收缩数据库 [4gv_g
--重建索引 Gfvz%%>l
DBCC REINDEX +1rJ ;G
DBCC INDEXDEFRAG 8w\&QX
--收缩数据和日志 4P.ry|2
DBCC SHRINKDB Sdn]
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DBCC SHRINKFILE ."2V:;;
3、压缩数据库 .]"
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dbcc shrinkdatabase(dbname) )}EwEM
4、转移数据库给新用户以已存在用户权限 87-oR}/r
exec sp_change_users_login 'update_one','newname','oldname' Y=5hm
go rkD(KG9E
5、检查备份集 %Z.!Bm:
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' EV}%D9:
6、修复数据库 Xd4~N:
ALTER DATABASE [dvbbs] SET SINGLE_USER D=8=wT2<
GO @8 pRIS"V
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK N7NK1<vw2
GO
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ALTER DATABASE [dvbbs] SET MULTI_USER (Lc%G~{
GO i}Y:o}
7、日志清除 _C##U; e!
SET NOCOUNT ON zUOYH4+
DECLARE @LogicalFileName sysname, 4:K9FqU
@MaxMinutes INT, -+z^{*\;N
@NewSize INT GK)hK-
USE tablename -- 要操作的数据库名 *2 [r?!
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 \d6A<(!=v
@MaxMinutes = 10, -- Limit on time allowed to wrap log. {BF$N#7
@NewSize = 1 -- 你想设定的日志文件的大小(M) Dd*C?6
-- Setup / initialize x[_+U4-/
DECLARE @OriginalSize int Ft07>E$/Q^
SELECT @OriginalSize = size 0g1uM:;
FROM sysfiles C 9DRVkjj
WHERE name = @LogicalFileName CkOd>Kn
SELECT 'Original Size of ' + db_name() + ' LOG is ' + f#!Ljjf$;
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 8r~4iVwg
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' rtPQ:CaA)?
FROM sysfiles wy7f7zIa
WHERE name = @LogicalFileName ?&[`=ZVn
CREATE TABLE DummyTrans a{y;Ub
(DummyColumn char (8000) not null) P:Bg()
DECLARE @Counter INT, /u?^s "C/
@StartTime DATETIME, 5-MI7I@l
@TruncLog VARCHAR(255) c+q4sNnE
SELECT @StartTime = GETDATE(), Q ml<JF
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' j_k!9"bt
DBCC SHRINKFILE (@LogicalFileName, @NewSize) VlKWWQj
EXEC (@TruncLog) O)&V}hU*
-- Wrap the log if necessary. J"|o g|Tz
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired m~2PpO
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) T8v>J4@t
AND (@OriginalSize * 8 /1024) > @NewSize 1>n@`M8}
BEGIN -- Outer loop. IF<jq\M
SELECT @Counter = 0 -?j'<g0
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) tFG&~tNc
BEGIN -- update >1W)J3
INSERT DummyTrans VALUES ('Fill Log') ,}J(&
DELETE DummyTrans q>,i `*
SELECT @Counter = @Counter + 1 1B 2>8N
END #Hq XC\~n
EXEC (@TruncLog) 9Y0w
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END DRal{?CH
SELECT 'Final Size of ' + db_name() + ' LOG is ' + gVb;sk^
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + P#iBwmwN+.
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' yAaMYF@
FROM sysfiles U1I2+;"#A
WHERE name = @LogicalFileName mzDbw-#
DROP TABLE DummyTrans oh|Q&R
SET NOCOUNT OFF 'v?Z~"w=
8、说明:更改某个表 tX)^$3A
exec sp_changeobjectowner 'tablename','dbo' >]FRHJo_
9、存储更改全部表 Y\s@'UoVN
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch xse8fGs
@OldOwner as NVARCHAR(128), 8^kw
@NewOwner as NVARCHAR(128) dtJ?J<m}
AS {"-uaH>,
DECLARE @Name as NVARCHAR(128) 3b~k)t4R
DECLARE @Owner as NVARCHAR(128) X"*pt5B6`
DECLARE @OwnerName as NVARCHAR(128) $)6y:t"
DECLARE curObject CURSOR FOR I t",WFE.
select 'Name' = name, af.yC[
'Owner' = user_name(uid) 67^?v)|
from sysobjects 2Lm.;l4YO
where user_name(uid)=@OldOwner ca5Ir<mL
order by name L2+~I<|>
OPEN curObject }qxwNmx
FETCH NEXT FROM curObject INTO @Name, @Owner 6V W&An[6r
WHILE(@@FETCH_STATUS=0) +hGr2%*0f
BEGIN ;~F&b:CyG
if @Owner=@OldOwner kyMWO*>|
begin \s<L2uRj
set @OwnerName = @OldOwner + '.' + rtrim(@Name) T=%,^
exec sp_changeobjectowner @OwnerName, @NewOwner 4 1q|R[js!
end r761vtC#
-- select @name,@NewOwner,@OldOwner zW8rC!
FETCH NEXT FROM curObject INTO @Name, @Owner bs/Vn'CE
END 8!sl) R
close curObject JZB7?@h%
deallocate curObject (}
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GO <A<N? `"
10、SQL SERVER中直接循环写入数据 /d*d'3{c
declare @i int N
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set @i=1 ^O}` i
while @i<30 )CKPzNf
begin ^z)p@sk#
insert into test (userid) values(@i) t[VA|1gG
set @i=@i+1 22$M6Qof]n
end "&W80,O3
小记存储过程中经常用到的本周,本月,本年函数 {W,&jC
Dateadd(wk,datediff(wk,0,getdate()),-1) kIrb;bZ+l
Dateadd(wk,datediff(wk,0,getdate()),6) ].w~FUa
Dateadd(mm,datediff(mm,0,getdate()),0) },+ &y^
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) o !bV;]
Dateadd(yy,datediff(yy,0,getdate()),0) d0YDNP%,_
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) muc6gwBp
上面的SQL代码只是一个时间段 54r/s#|-3
Dateadd(wk,datediff(wk,0,getdate()),-1) q8#zv_>K
Dateadd(wk,datediff(wk,0,getdate()),6) Qq+$ea?>
就是表示本周时间段. x}B3h9]
下面的SQL的条件部分,就是查询时间段在本周范围内的: [7_1GSS1
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) hv
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而在存储过程中 7Ji|x{``
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) \SKobO?qI
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) @L0xU??"|