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。 7~b=G
jfmHc(fX4
C,;T/9
一、基础 +kA>^
1、说明:创建数据库 1oKF-";u(
CREATE DATABASE database-name .8o?`
2、说明:删除数据库 h/oRWl0r
drop database dbname Ov$>CA
3、说明:备份sql server |Gp!#D0b
--- 创建 备份数据的 device L`'#}#O l
USE master /ILj}g'
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' OlU')0Y
--- 开始 备份 ->Z9j(JU
BACKUP DATABASE pubs TO testBack )6+Z9 9w
4、说明:创建新表 ))T@U?r
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) o<h2]TN
根据已有的表创建新表: JJ:p A_uX
A:create table tab_new like tab_old (使用旧表创建新表) ,LE 15},
B:create table tab_new as select col1,col2... from tab_old definition only vCvjb\S
5、说明:删除新表 ML _$/
drop table tabname 1G}f83yR
6、说明:增加一个列 4^r4O#
Alter table tabname add column col type [8C|v61Y
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。 vHJOpQmt~
7、说明:添加主键: Alter table tabname add primary key(col) IRhi1{K$"
说明:删除主键: Alter table tabname drop primary key(col) 6jw9p+.
8、说明:创建索引:create [unique] index idxname on tabname(col....) Clz.
p
删除索引:drop index idxname is~"yE7
注:索引是不可更改的,想更改必须删除重新建。 #ovausK[7
9、说明:创建视图:create view viewname as select statement n?KhBJx 4
删除视图:drop view viewname q
~%'V
10、说明:几个简单的基本的sql语句 [}Q_T.4)E
选择:select * from table1 where 范围 p9>{X\eT:
插入:insert into table1(field1,field2) values(value1,value2) ]I,(^Xq3a(
删除:delete from table1 where 范围 }VU^ 8D
更新:update table1 set field1=value1 where 范围 C/$bgK[ev
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! s5bqS'%
排序:select * from table1 order by field1,field2 [desc] jgvzp
总数:select count as totalcount from table1 SND@#?hiO
求和:select sum(field1) as sumvalue from table1 sLKk1A
平均:select avg(field1) as avgvalue from table1 ,`Keqfx
最大:select max(field1) as maxvalue from table1 L<XAvg
最小:select min(field1) as minvalue from table1 ?^whK<"]
,?>{M
NX[-Y]t
#fYRsVQ
11、说明:几个高级查询运算词 K`=9"v'f+
|,bP`Z
&\>=4)HB;
A: UNION 运算符 ) $`}~
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 Y#,&Tu
B: EXCEPT 运算符 s.X
.SJ
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 N \~}`({
C: INTERSECT 运算符 ')Q
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 c@E;v<r'
注:使用运算词的几个查询结果行必须是一致的。 c;?J
12、说明:使用外连接 v9\U2j
A、left outer join: 3F?7oMNIh
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 0BwxPD#6bv
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c p4F%FS:`
B:right outer join: Y\,aJL$
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。 ["O_Phb|
C:full outer join: yk0tA
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。 pG6?"*Fz;
|oWl9j]Z
uTdx`>M,O
二、提升 {RGQX"k
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 7lx"
X0w*m
法一:select * into b from a where 1<>1 {Gr"lOi*@
法二:select top 0 * into b from a r6eZ-V`4
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) _1?nLx7n
insert into b(a, b, c) select d,e,f from b; XDY QV.Bv
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) 5tI#UBha
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 zv7)JH7EV&
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. \0W0 o5c$
4、说明:子查询(表名1:a 表名2:b) GlHP`&;UH
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) mm9uhlV8
5、说明:显示文章、提交人和最后回复时间 =F2`X#x_j
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b {?;qy\m]o
6、说明:外连接查询(表名1:a 表名2:b) `;=-71Gn~
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c p[O\}MAd#
7、说明:在线视图查询(表名1:a ) +7Uv|LZ~@
select * from (SELECT a,b,c FROM a) T where t.a > 1;
0ijYE
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 v8YF+N
select * from table1 where time between time1 and time2 }4g$aTc
select a,b,c, from table1 where a not between 数值1 and 数值2 J(G-c5&=
9、说明:in 的使用方法 y|0!sNg
select * from table1 where a [not] in ('值1','值2','值4','值6')
Y(
10、说明:两张关联表,删除主表中已经在副表中没有的信息 =P9Tc"2PN
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) zs(P2$
11、说明:四表联查问题: e-Oz`qW~
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 ..... xHCdtloi?I
12、说明:日程安排提前五分钟提醒 @Di!~e6
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 AdpJ4}|0
13、说明:一条sql 语句搞定数据库分页 gg/ts]$
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 YQ@2p?4m
14、说明:前10条记录 p"FWAC!
select top 10 * form table1 where 范围 ? 'qyI^m@
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.) v, CWE
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) xk
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 `W >Sss
(select a from tableA ) except (select a from tableB) except (select a from tableC) TCFr-*x
17、说明:随机取出10条数据 ;PB_@Zg
select top 10 * from tablename order by newid() +1a3^A\
18、说明:随机选择记录 M&jlUr&l
select newid() ]h#QA;
19、说明:删除重复记录 T, +=ka$
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) <-mhz`^
20、说明:列出数据库里所有的表名 NBXhcfF
select name from sysobjects where type='U' it-]-=mqb
21、说明:列出表里的所有的 0x,**6
select name from syscolumns where id=object_id('TableName') !>"fDz<w`
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。 C;5`G
*e
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 $|g
;
显示结果: HOx+umjxW
type vender pcs Q 5hOVD%
电脑 A 1 .p]rS
=#
电脑 A 1 Dpwqg3,
光盘 B 2 bSz@@s.
光盘 A 2 V%{WH}
手机 B 3 ')}itS8
手机 C 3 {+ Ibi{
23、说明:初始化表table1 .hM t:BMf*
TRUNCATE TABLE table1 E]v]fy"
24、说明:选择从10到15的记录 Zb&pH~ 7
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc !g`I*ZE+e
w=CzPNRHH!
q'/o=De
o%f:BJS
三、技巧 v`c;1 ?=,q
1、1=1,1=2的使用,在SQL语句组合时用的较多 eh%{BXW[p
"where 1=1" 是表示选择全部 "where 1=2"全部不选, uts>4r>+
如: H0!$aO
if @strWhere !='' @( \R@`#
begin n!.=05OtX
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere `dD_"Hdt
end -uu&{$
else FW5v
1s=
begin @ze2'56F}
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' Q lA?dXQ
end 5HsF#
我们可以直接写成 qe'ssX;
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere )7]yzc
2、收缩数据库 FrUqfTi+W
--重建索引 /\_n5XI1
DBCC REINDEX +I-BqA9
DBCC INDEXDEFRAG 6:L2oW 6}{
--收缩数据和日志 :<s`)
DBCC SHRINKDB ok [_Z;
DBCC SHRINKFILE K@JaN/OM
3、压缩数据库 ]v0Z[l>yf
dbcc shrinkdatabase(dbname) SSxz1y
4、转移数据库给新用户以已存在用户权限 V%)Tu{L
exec sp_change_users_login 'update_one','newname','oldname' S*>T%#F6Uo
go REgM
5、检查备份集 qp)Wt6 k?
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' %.D!J",\/K
6、修复数据库 Be6+YM5Cl
ALTER DATABASE [dvbbs] SET SINGLE_USER xkw=os
GO dA (n,@{
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK z;dRzwL
GO tHo|8c~[
ALTER DATABASE [dvbbs] SET MULTI_USER rQ_]%ies8
GO t,dm3+R
7、日志清除 jVLJqWP'!
SET NOCOUNT ON Xz)qtDN|(
DECLARE @LogicalFileName sysname, <5mv8'{L
@MaxMinutes INT, u]7wd3(
@NewSize INT a??8)=0|}
USE tablename -- 要操作的数据库名 AC'_#nPL#
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 s*_fRf:
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 1og+(m`BL
@NewSize = 1 -- 你想设定的日志文件的大小(M) G&Dl($
-- Setup / initialize SASLeGaV
DECLARE @OriginalSize int jI0gf&v8
SELECT @OriginalSize = size c|`$
h
FROM sysfiles }IZw6KiN
WHERE name = @LogicalFileName *Ow2,{Nn
SELECT 'Original Size of ' + db_name() + ' LOG is ' + W;cYg.W2
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + tk*-Cx?_
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' Ncsh{.
FROM sysfiles ;9WUt,R
WHERE name = @LogicalFileName W7b
m}JHn
CREATE TABLE DummyTrans },#7
(DummyColumn char (8000) not null) p}h.2)PO
DECLARE @Counter INT, rX /'
@StartTime DATETIME, +&S6se4
@TruncLog VARCHAR(255) n}[S
SELECT @StartTime = GETDATE(), ;1PJS_@rX
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' j)Ak:l%a
DBCC SHRINKFILE (@LogicalFileName, @NewSize) JKfJ%yy |
EXEC (@TruncLog) !H)-
-- Wrap the log if necessary. enZZ+|h
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired cV0CI&
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) b}ya9tCl;
AND (@OriginalSize * 8 /1024) > @NewSize >p@b$po
BEGIN -- Outer loop. ?>7-a~*A@
SELECT @Counter = 0 KK #E
qJ
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) 9(q(;|;Hp
BEGIN -- update @!'}=?`
INSERT DummyTrans VALUES ('Fill Log') 3 (\D.Z
DELETE DummyTrans K0_gMi+bR
SELECT @Counter = @Counter + 1 @v^j<B
END }mK,Bi?bj
EXEC (@TruncLog) ;*t#:U*
END -y$6gCRY
SELECT 'Final Size of ' + db_name() + ' LOG is ' + }zf!mlk
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + &mmaoWR
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' 5qW>#pTFVV
FROM sysfiles rIJPgF
WHERE name = @LogicalFileName
UWqD)6
DROP TABLE DummyTrans A]5];c
SET NOCOUNT OFF YS){N=g&'
8、说明:更改某个表 Y1I)w^}:
exec sp_changeobjectowner 'tablename','dbo' A] 'jsv!+
9、存储更改全部表 ,!@ MLn
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch /z4c>)fV
@OldOwner as NVARCHAR(128), Y8]@y0(
@NewOwner as NVARCHAR(128) dd<l;4(
AS z)U7
DECLARE @Name as NVARCHAR(128) Dqii60
DECLARE @Owner as NVARCHAR(128) qD ?`Yd
DECLARE @OwnerName as NVARCHAR(128) @-L]mLY
DECLARE curObject CURSOR FOR bTrusSAl
select 'Name' = name, <7F-WR/2n
'Owner' = user_name(uid) dH;2OWM
from sysobjects AQ@)'
where user_name(uid)=@OldOwner rvy%8%e?
order by name hEu_mw#
OPEN curObject 0V>HoH
FETCH NEXT FROM curObject INTO @Name, @Owner ?.%dQ0
WHILE(@@FETCH_STATUS=0) r>FwJm!
BEGIN ]#^v754X^T
if @Owner=@OldOwner ]S[/a
begin .4[3r[
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 9l&q}
exec sp_changeobjectowner @OwnerName, @NewOwner gee~>l
end m<-!~ ew
-- select @name,@NewOwner,@OldOwner Sk>=C0f:
FETCH NEXT FROM curObject INTO @Name, @Owner !pw)sO~
END Vi-Ph;6[
close curObject \q1tT!]
deallocate curObject $1|E(d1
GO ~Ay)kv;
10、SQL SERVER中直接循环写入数据 HrvyI)4{
declare @i int 2<I=xWwFA
set @i=1 f%@~|:G:
while @i<30 =dDPQZEin
begin `s T;\
insert into test (userid) values(@i) ,P`NtTN-
set @i=@i+1 /CNsGx%%
end 5kTs7zJ^
小记存储过程中经常用到的本周,本月,本年函数 >x;\H(g
Dateadd(wk,datediff(wk,0,getdate()),-1) aF^NYe
Dateadd(wk,datediff(wk,0,getdate()),6) 94ruQ/
Dateadd(mm,datediff(mm,0,getdate()),0) iLuC_.'u=
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) }8Y! -qX
Dateadd(yy,datediff(yy,0,getdate()),0) ,GYQ,9:
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) CL1*pL
上面的SQL代码只是一个时间段 G]f|?
Dateadd(wk,datediff(wk,0,getdate()),-1) 8CZfz!2
Dateadd(wk,datediff(wk,0,getdate()),6) O;<wDh)Yt
就是表示本周时间段. M['O`^
下面的SQL的条件部分,就是查询时间段在本周范围内的: 77O$^fG2
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) [m0X kvd
而在存储过程中 3<
?+Yhq
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) yj&GJuNb~
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) cZ:jht