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。 ,8DjQz0ZPo
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一、基础 VT;cz6"6b4
1、说明:创建数据库 /1hcw|cfC
CREATE DATABASE database-name >/.Ae8I)
2、说明:删除数据库 T+:GYab/
drop database dbname &}0#(Fa`
3、说明:备份sql server ("=B,%F_
--- 创建 备份数据的 device 0{stIgB$
USE master l5U ^lc
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 1V]j8
--- 开始 备份 R?:(~ X\
BACKUP DATABASE pubs TO testBack .|y{1?f_
4、说明:创建新表 ko~e*31_E
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) |jKFk.M
根据已有的表创建新表: G.^^zmsM`
A:create table tab_new like tab_old (使用旧表创建新表)
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B:create table tab_new as select col1,col2... from tab_old definition only j^Ln\N]^
5、说明:删除新表 |e2s{J2
drop table tabname
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6、说明:增加一个列 '~x jaa;.
Alter table tabname add column col type \obM}caT
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。 Hc\oR(L
7、说明:添加主键: Alter table tabname add primary key(col) KPa@~rU
说明:删除主键: Alter table tabname drop primary key(col) .zJZ*\2ob
8、说明:创建索引:create [unique] index idxname on tabname(col....) py\/m]
删除索引:drop index idxname %kk~qvW
注:索引是不可更改的,想更改必须删除重新建。 X-SR0x
9、说明:创建视图:create view viewname as select statement sv#/ 78 ~|
删除视图:drop view viewname *#B"%;Ln
10、说明:几个简单的基本的sql语句 {HP.HK
选择:select * from table1 where 范围 B\>3[_n
插入:insert into table1(field1,field2) values(value1,value2) a*o k*r
删除:delete from table1 where 范围 p8z"Jn2P
更新:update table1 set field1=value1 where 范围 QhPpo#^
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! o H]FT{
排序:select * from table1 order by field1,field2 [desc] E{'\(6z_
总数:select count as totalcount from table1 eS2VLVxu
求和:select sum(field1) as sumvalue from table1 1tH#QZIT
平均:select avg(field1) as avgvalue from table1 q94*2@KV
最大:select max(field1) as maxvalue from table1 DjiWg(X
最小:select min(field1) as minvalue from table1 wtfM}MW\
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11、说明:几个高级查询运算词 w)Y}hlcq
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A: UNION 运算符 Jv D`RUh
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。 'V*8'?
B: EXCEPT 运算符 ^I!gteU;
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。 L$}'6y/@
C: INTERSECT 运算符 `e+eL*rZ~
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 QtfLJ5vi
注:使用运算词的几个查询结果行必须是一致的。 |d_ rK2
12、说明:使用外连接 -V}ZbXJD
A、left outer join: 4,ewp coC%
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 p;{w0uld"
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c #M8>)o c
B:right outer join: '59l.
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 4\2~wSr
C:full outer join: MZSyu
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 Nv\<>gA:
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二、提升 b/eo]Id ]
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) KnYHjJa
法一:select * into b from a where 1<>1 U,nQnD"!t&
法二:select top 0 * into b from a zKaEh
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 8?k.4{?
insert into b(a, b, c) select d,e,f from b; K?mly$
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) IeJ@G)
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 H3qL&xL
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. g?!;04
4、说明:子查询(表名1:a 表名2:b) SP5t=#M6
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) pPZ^T5-ks
5、说明:显示文章、提交人和最后回复时间 xqaw00,s
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b }i2dXC/
6、说明:外连接查询(表名1:a 表名2:b) I,!>ZG@6
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ^ px)W,O
7、说明:在线视图查询(表名1:a ) eR5+1b
select * from (SELECT a,b,c FROM a) T where t.a > 1; r#K" d
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 .s<tQU
select * from table1 where time between time1 and time2 4$b9<:M_
select a,b,c, from table1 where a not between 数值1 and 数值2 hdee]qLS
9、说明:in 的使用方法 ?C9>bKo*2H
select * from table1 where a [not] in ('值1','值2','值4','值6') QjwCY=PK!
10、说明:两张关联表,删除主表中已经在副表中没有的信息 fT_swhIO
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) %q,^A+=
11、说明:四表联查问题: .Dg'MMBM
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... 2E}^'o
12、说明:日程安排提前五分钟提醒 =6+j
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SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 _k.gVm
13、说明:一条sql 语句搞定数据库分页 -<B{?D
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 .[#bOp*
14、说明:前10条记录 ,<?M/'4}G
select top 10 * form table1 where 范围 j<*`?V^
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) q9"~sCH
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) &,@wLy^T
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 _i{4 4zE
(select a from tableA ) except (select a from tableB) except (select a from tableC) q CB9z
17、说明:随机取出10条数据 QYTwGThWR
select top 10 * from tablename order by newid() uDi#a~m@
18、说明:随机选择记录 hKW!kA=gZ
select newid() @Ao E>
19、说明:删除重复记录 \ g[A{
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) o] 7U;W
20、说明:列出数据库里所有的表名 7?JcB?G4
select name from sysobjects where type='U' A?829<
21、说明:列出表里的所有的 H=k*;'
select name from syscolumns where id=object_id('TableName') r#[YBaCZJ
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 mF !=H%
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type 7'xds
显示结果: F
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type vender pcs T"m(V/L$W
电脑 A 1 h/%Hk;|9
电脑 A 1 >ak53Ij$
光盘 B 2 vXM``|
光盘 A 2 1"CbuV
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手机 B 3 )WFSUZ~
手机 C 3 &c!=< <5M
23、说明:初始化表table1 dO[w3\~
TRUNCATE TABLE table1 "ci<W_lx
24、说明:选择从10到15的记录 ?k:i3$
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc %lU$;cY
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三、技巧 XDJQO /qN
1、1=1,1=2的使用,在SQL语句组合时用的较多 BDg6ZI<n
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 1xo<V5
如: Uq6..<#
if @strWhere !='' JZQ$*K
begin Ucnit^,
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere HiG&`:P>q
end 'm=9&?0S
else "zO+!h'o
begin <ZNa`
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' | JL47FR
end wWflZ"%
我们可以直接写成 .0q %A1H
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ;.h5; `&
2、收缩数据库 |C S[>0mV!
--重建索引 AsM""x1Ix
DBCC REINDEX \?fl%r2
DBCC INDEXDEFRAG N3H!ptn37
--收缩数据和日志 ;r[=q u\
DBCC SHRINKDB T+2I:W%
DBCC SHRINKFILE }h>e=<
3、压缩数据库 <..%@]+
dbcc shrinkdatabase(dbname) <96ih$5D1
4、转移数据库给新用户以已存在用户权限 /7h%sCX
exec sp_change_users_login 'update_one','newname','oldname' ?kb\%pcK
go TR@$$RrU
5、检查备份集 (.!q~G
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' i\rI j0+
6、修复数据库 eeb8v:4
ALTER DATABASE [dvbbs] SET SINGLE_USER W^&t8d2
GO +.HQ+`8z]
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 9&'Mb[C`"
GO Y@u{73H
ALTER DATABASE [dvbbs] SET MULTI_USER YKl!M/
GO qTyU1RU$9^
7、日志清除 lLtC9:
SET NOCOUNT ON \{+7`4g
DECLARE @LogicalFileName sysname, S,S_BB<Y[b
@MaxMinutes INT, QbqLj>-AJ
@NewSize INT _zm<[0(
USE tablename -- 要操作的数据库名 Ed*`d>
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 N M~e
@MaxMinutes = 10, -- Limit on time allowed to wrap log. G68N@g
@NewSize = 1 -- 你想设定的日志文件的大小(M) ?67j+)
-- Setup / initialize rT}d<cSf
DECLARE @OriginalSize int ZVIBmx
SELECT @OriginalSize = size 0#*\o1r\p
FROM sysfiles B{1+0k
WHERE name = @LogicalFileName NnHM$hEI"U
SELECT 'Original Size of ' + db_name() + ' LOG is ' + <)n
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + n7<<}wcV
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 6o A0a\G'
FROM sysfiles ~?b(2gn
WHERE name = @LogicalFileName 9y]$c1
CREATE TABLE DummyTrans ?QVD)JI*k
(DummyColumn char (8000) not null) ^QW%<X
DECLARE @Counter INT, \wDOE(>
@StartTime DATETIME, @1Zf&'/6
@TruncLog VARCHAR(255) [V jd)%
SELECT @StartTime = GETDATE(), ~Nc]`95
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 7 cIVK}&
DBCC SHRINKFILE (@LogicalFileName, @NewSize) bR&hI9`%F
EXEC (@TruncLog)
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-- Wrap the log if necessary. U-n33ty`H
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired BTd'bD~EA
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) At bqj?
AND (@OriginalSize * 8 /1024) > @NewSize Vj?.' (
BEGIN -- Outer loop. & vLX
SELECT @Counter = 0 zRE7 w:
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ":-)mfgGU
BEGIN -- update &aF_y_f\
INSERT DummyTrans VALUES ('Fill Log') B|GJboQ
DELETE DummyTrans ?ST}0F00}
SELECT @Counter = @Counter + 1 ]-PF? 8
END 1@nR.v"$
EXEC (@TruncLog) [Z5x_.k"I
END HWefuj
SELECT 'Final Size of ' + db_name() + ' LOG is ' + y6PAXvv'{
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 3.dUMJ$_
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' "!Qhk3*
FROM sysfiles T:!sfhrZ~<
WHERE name = @LogicalFileName 'Ux_X:,:;
DROP TABLE DummyTrans s*8hN*A/,
SET NOCOUNT OFF /d{L]*v)]
8、说明:更改某个表 ;!~;05^iD
exec sp_changeobjectowner 'tablename','dbo' PO%]Jme
9、存储更改全部表 NI^Y%N
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch !<YRocQY
@OldOwner as NVARCHAR(128), }zobIfIF
@NewOwner as NVARCHAR(128) f$Ap\(.
AS H|TzD"2N
DECLARE @Name as NVARCHAR(128) .y\HQ^j
DECLARE @Owner as NVARCHAR(128) I Mv^ 9T:
DECLARE @OwnerName as NVARCHAR(128) x#YOz7.
DECLARE curObject CURSOR FOR Zgg 7pL)#c
select 'Name' = name, q!H3JL
'Owner' = user_name(uid) <m6Xh^Ko;
from sysobjects Z956S$gS
where user_name(uid)=@OldOwner _+Q$h4t
order by name )Xh_q3=
OPEN curObject c\]L
FETCH NEXT FROM curObject INTO @Name, @Owner .gPsJ?b
WHILE(@@FETCH_STATUS=0) 18n84RkI9
BEGIN fN4pG*D
if @Owner=@OldOwner *g,?13Q_
begin asq/_`
set @OwnerName = @OldOwner + '.' + rtrim(@Name) fgp7 |;Y
exec sp_changeobjectowner @OwnerName, @NewOwner oOL3O@)w>
end g~y9j88?
-- select @name,@NewOwner,@OldOwner Fd\XDc[g
FETCH NEXT FROM curObject INTO @Name, @Owner ipzUF o<w
END 8;!Eqyt
close curObject eB\r/B]
deallocate curObject 6m.Ku13;
GO EU@mrm?
10、SQL SERVER中直接循环写入数据 3H%HJS
declare @i int *3ne(c
set @i=1 Xou#38&p>
while @i<30 o5D" <-=>
begin b"Mq7&cf
insert into test (userid) values(@i) |O)deiJRy
set @i=@i+1 y[zA[H:
end vW{cBy
小记存储过程中经常用到的本周,本月,本年函数 h/fCCfO,
Dateadd(wk,datediff(wk,0,getdate()),-1) mWusRgj+8
Dateadd(wk,datediff(wk,0,getdate()),6) `HM3YC
Dateadd(mm,datediff(mm,0,getdate()),0) ) ]%9Tgn
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) avpw+M6+
Dateadd(yy,datediff(yy,0,getdate()),0) NqZRS>60v
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) Ij#a
上面的SQL代码只是一个时间段 TN
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Dateadd(wk,datediff(wk,0,getdate()),-1) jSFN/C.9h
Dateadd(wk,datediff(wk,0,getdate()),6) g&"(- :
就是表示本周时间段. b66X])+4jE
下面的SQL的条件部分,就是查询时间段在本周范围内的: zkp
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Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) Ke ?uE
而在存储过程中 bS<@Rd{g
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) nP3GI:mjL
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) |%}s$*s