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>1Cx4s5
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一、基础 X(MS!R V
1、说明:创建数据库 '!8-/nlv1
CREATE DATABASE database-name ocJG4#
2、说明:删除数据库 RK &>!^
drop database dbname *wj5( B<y
3、说明:备份sql server 16~E
--- 创建 备份数据的 device z]+L=+,,
USE master S7Ty}?E@
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' Ec3tfcNhR
--- 开始 备份 ""a$[[ %WC
BACKUP DATABASE pubs TO testBack
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4、说明:创建新表 H(K
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create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) [K\b"^=<
根据已有的表创建新表: 2wIJ;rh
A:create table tab_new like tab_old (使用旧表创建新表) !e~[U-
B:create table tab_new as select col1,col2... from tab_old definition only C`ky=
5、说明:删除新表 >20dK
drop table tabname `(0B09~7
6、说明:增加一个列 z<vh8dNl
Alter table tabname add column col type 4,c6VCw3+
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 Z%B6J>;u M
7、说明:添加主键: Alter table tabname add primary key(col) X(*O$B{
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说明:删除主键: Alter table tabname drop primary key(col) bNVeL$'
8、说明:创建索引:create [unique] index idxname on tabname(col....) w,FPL&{
删除索引:drop index idxname &4S2fWx
注:索引是不可更改的,想更改必须删除重新建。 L}Y.xi
9、说明:创建视图:create view viewname as select statement /}m*|cG/
删除视图:drop view viewname o!":mJy
10、说明:几个简单的基本的sql语句 yvoz 3_!
选择:select * from table1 where 范围 8Ejb/W_
插入:insert into table1(field1,field2) values(value1,value2) *1<kYrB
删除:delete from table1 where 范围 iI";m0Ny
更新:update table1 set field1=value1 where 范围 Gw$ 5<%sB
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! ~<n.5q%Z
排序:select * from table1 order by field1,field2 [desc] )B0%"0?`8
总数:select count as totalcount from table1 0O>ClE~P
求和:select sum(field1) as sumvalue from table1 ~;#}aQYo
平均:select avg(field1) as avgvalue from table1 mA+:)?e5~
最大:select max(field1) as maxvalue from table1 ikV;]ox
最小:select min(field1) as minvalue from table1 mL48L57Z
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11、说明:几个高级查询运算词 %NxQb'
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A: UNION 运算符 oIj=ba(n1
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^+D,)#D^
B: EXCEPT 运算符 U*$xR<8v
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 @i; )`k5b
C: INTERSECT 运算符 @nY]S\if
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 src+z#
注:使用运算词的几个查询结果行必须是一致的。 `{G&i\"n
12、说明:使用外连接 >9dD7FH
A、left outer join: TjEXR$:<
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。 =#S.t:HQ*
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 kY~4AH
B:right outer join: j/*1zu8Y
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。 *b.
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C:full outer join: nJ2x;';lA
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。 P U/<7P*
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二、提升 |2u=3#Jp
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ?!U[~Gq
法一:select * into b from a where 1<>1 Q7$o&N{
法二:select top 0 * into b from a "a8E0b
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) .PUp3X-
insert into b(a, b, c) select d,e,f from b; zTw"5N
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) _y^r==
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 5o dT\>Sn
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where..
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4、说明:子查询(表名1:a 表名2:b) o'!=x$Ky
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) ,
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5、说明:显示文章、提交人和最后回复时间 1
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select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b @a?7D;+<
6、说明:外连接查询(表名1:a 表名2:b) 5dj@N3ZX7;
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c -{xk&EB^$5
7、说明:在线视图查询(表名1:a ) 9_?xAJ
select * from (SELECT a,b,c FROM a) T where t.a > 1; ^Fco'nlM
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 0- )K_JV
select * from table1 where time between time1 and time2 E=p+z"Ui
select a,b,c, from table1 where a not between 数值1 and 数值2 Y"GNJtsL "
9、说明:in 的使用方法 n|~y
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select * from table1 where a [not] in ('值1','值2','值4','值6')
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10、说明:两张关联表,删除主表中已经在副表中没有的信息 67II9\/
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) +O.-o/
11、说明:四表联查问题: 2M-[x"\1/
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 ..... P9
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12、说明:日程安排提前五分钟提醒 &3[oM)-V
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ^es]jng`
13、说明:一条sql 语句搞定数据库分页 W-=6:y#A
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 tNi>TkC}`
14、说明:前10条记录 `x9Eo4(/
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.) ##7y|AwK
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) GkIY2PD
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 N7+L@CC6T
(select a from tableA ) except (select a from tableB) except (select a from tableC) 6QX m]<
17、说明:随机取出10条数据 `OBzOM
select top 10 * from tablename order by newid() kt/,& oKI
18、说明:随机选择记录 s{Z)<n03
select newid() MY^{[#Q
19、说明:删除重复记录 F~mIV;BP
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) {arqcILr
20、说明:列出数据库里所有的表名 ZD]1C~)
select name from sysobjects where type='U' "La;$7ds
21、说明:列出表里的所有的 r!mRUw'u
select name from syscolumns where id=object_id('TableName') ?l0Qi
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 !qt2,V
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type Pb#M7=J/
显示结果: g"! (@]L!@
type vender pcs "?I#!t%'
电脑 A 1 TN2Ln?[xU
电脑 A 1 Gmz^vpQ]t
光盘 B 2 "jFf}"
光盘 A 2 to'7o8Z
手机 B 3
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手机 C 3 cuhp4!!
23、说明:初始化表table1 Hc)z:x;Sj
TRUNCATE TABLE table1 NBYJ'nA%;f
24、说明:选择从10到15的记录 HC%Hbc~S_Q
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc Z7;V}[wie
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三、技巧 P!eo#b^S
1、1=1,1=2的使用,在SQL语句组合时用的较多 H3A$YkK [
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 8h=t%zMSb
如: qb>41j9_t
if @strWhere !='' Zse&{
begin I\~[GsDY
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere >HP
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end [n2B6Px
else 'NEl`v*<P
begin \Z[1m[{
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' b3ohTmy4(
end /eF@a!
我们可以直接写成 S
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ;M:AcQZ|_
2、收缩数据库 UVo`jb|>
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--重建索引 aSzI5J]/=
DBCC REINDEX `q^#u
DBCC INDEXDEFRAG
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--收缩数据和日志 ge~@}iO@
DBCC SHRINKDB *]$B 9zVs!
DBCC SHRINKFILE DXs an
3、压缩数据库 :<QknU}dwy
dbcc shrinkdatabase(dbname) d*@T30
4、转移数据库给新用户以已存在用户权限 e97G]XLR
exec sp_change_users_login 'update_one','newname','oldname' <xI<^r'C9e
go X?5{2ulrI
5、检查备份集 Hn|W3U
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' )4yP(6|lx
6、修复数据库 8dGsV5" *
ALTER DATABASE [dvbbs] SET SINGLE_USER BI1M(d#1L"
GO ,>;21\D
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK aZFpt/.d
GO $DbnPZ2$
ALTER DATABASE [dvbbs] SET MULTI_USER 17LhgZs&
GO 5 ~Wg=u<6
7、日志清除 Z>hTL_|]a{
SET NOCOUNT ON ;*A'2ymXUT
DECLARE @LogicalFileName sysname, #-/W?kD
@MaxMinutes INT, wZqYtJ
@NewSize INT oz)[-
USE tablename -- 要操作的数据库名 "H-s_Y#
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 dljE.peL
@MaxMinutes = 10, -- Limit on time allowed to wrap log. c4Ebre-Oa
@NewSize = 1 -- 你想设定的日志文件的大小(M) <DF3!r
-- Setup / initialize qE[S>/R"
DECLARE @OriginalSize int 3JnpI,By
SELECT @OriginalSize = size |cvU2JI@
FROM sysfiles F2"fOS
WHERE name = @LogicalFileName +jm,nM9
SELECT 'Original Size of ' + db_name() + ' LOG is ' + \TQZZ_Z
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + @- U\!Tf
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' _D '(R
FROM sysfiles [&)]-2w2
WHERE name = @LogicalFileName 5\ mRH
CREATE TABLE DummyTrans uYh!04u
(DummyColumn char (8000) not null) 02;jeZ#z
DECLARE @Counter INT, /0s1;?
@StartTime DATETIME, 3$|/7(M&DA
@TruncLog VARCHAR(255) Pvxb6\G&d
SELECT @StartTime = GETDATE(), -`O{iHfM|P
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' f1 ;
DBCC SHRINKFILE (@LogicalFileName, @NewSize) %w`d
EXEC (@TruncLog) m'o dVZ7
-- Wrap the log if necessary. .wfydu)3
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired SE'Im
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) TEtmmp0OD
AND (@OriginalSize * 8 /1024) > @NewSize z0z@LA4k6@
BEGIN -- Outer loop. }w0pi
SELECT @Counter = 0 r&gvP|W%
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) kSAVFzUS
BEGIN -- update XiUq#84Q
INSERT DummyTrans VALUES ('Fill Log') UP~28%>X
DELETE DummyTrans `m,4#P-kj
SELECT @Counter = @Counter + 1 (MwRe?Ih
END ,}oAc
EXEC (@TruncLog) ;Afz`Se1@
END p~D}Iyww1_
SELECT 'Final Size of ' + db_name() + ' LOG is ' + djd/QAfSC
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + )U/jD
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' Rh>B#
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FROM sysfiles $7x2TiAL
WHERE name = @LogicalFileName s8h*nZ)v
DROP TABLE DummyTrans <b 5DX
SET NOCOUNT OFF Aoe\\'O|V
8、说明:更改某个表 F/5&:e?( )
exec sp_changeobjectowner 'tablename','dbo' :eN&wQ5q
9、存储更改全部表 tsXKhS;/w
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch +
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@OldOwner as NVARCHAR(128), zl0{lV
@NewOwner as NVARCHAR(128) Ak'=l;
AS _imuyt".+
DECLARE @Name as NVARCHAR(128) {bj!]j
DECLARE @Owner as NVARCHAR(128) #<{v~sVp&
DECLARE @OwnerName as NVARCHAR(128) MIMC(<
DECLARE curObject CURSOR FOR X/5m}-6d]
select 'Name' = name, `#""JTA"
'Owner' = user_name(uid) i]8O?Ab>?
from sysobjects zakhJ
where user_name(uid)=@OldOwner dlu*s(O"
order by name
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OPEN curObject "{q#)N
FETCH NEXT FROM curObject INTO @Name, @Owner #{i*9'
WHILE(@@FETCH_STATUS=0) waMF~#PJlt
BEGIN }7 N6nZj`
if @Owner=@OldOwner = Xgo}g1
begin "Q?+T:D8|
set @OwnerName = @OldOwner + '.' + rtrim(@Name) HDe\Oty_
exec sp_changeobjectowner @OwnerName, @NewOwner CPz<iU
end ?ZF):}rvZ
-- select @name,@NewOwner,@OldOwner Ailq,c
FETCH NEXT FROM curObject INTO @Name, @Owner 6v`3/o
END GZ%vFje_
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close curObject -/f$s1
deallocate curObject *+M#D^qo
GO {j2V k)\[i
10、SQL SERVER中直接循环写入数据 mLCDN1UO{
declare @i int }b_Ob
set @i=1 #QNN;&L]R
while @i<30 AA\a#\#Z3
begin 'l*X?ccKy
insert into test (userid) values(@i) H& |/|\8F
set @i=@i+1 \ .xS
end v~$V
小记存储过程中经常用到的本周,本月,本年函数 (W1$+X
Dateadd(wk,datediff(wk,0,getdate()),-1) ">V1II
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Dateadd(wk,datediff(wk,0,getdate()),6) >|f"EK}m!
Dateadd(mm,datediff(mm,0,getdate()),0) l\<.*6r
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) fO<40!%9cQ
Dateadd(yy,datediff(yy,0,getdate()),0) xyL"U*
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) Z.VKG1e}
上面的SQL代码只是一个时间段 tv#oEM9esl
Dateadd(wk,datediff(wk,0,getdate()),-1) kK&w5'
Dateadd(wk,datediff(wk,0,getdate()),6) WzIUHNn'I
就是表示本周时间段. IJ^~,+
下面的SQL的条件部分,就是查询时间段在本周范围内的: 'a#lBzu\b
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 5`h$^l/
而在存储过程中 lM-9 J?j
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) $n<a`PdH
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) h"FI]jK|}