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。 uV|F3'jT
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一、基础 (YJ2-
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1、说明:创建数据库 H2iIBGu|L
CREATE DATABASE database-name M._h=wX{}
2、说明:删除数据库 t!4 (a0\$F
drop database dbname hq4&<Zr(
3、说明:备份sql server P%B|HnG^
--- 创建 备份数据的 device mN-O{k0\
USE master +:Xg7H*
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' FM%WMyb[
--- 开始 备份 ^/%o
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BACKUP DATABASE pubs TO testBack wsdZwik
4、说明:创建新表 sudh=_+>
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) &$ }6:
根据已有的表创建新表: MoxWnJy}
A:create table tab_new like tab_old (使用旧表创建新表) q AVypP?J
B:create table tab_new as select col1,col2... from tab_old definition only |>P:R4P
5、说明:删除新表 [`|t( E'
drop table tabname /#5rt&q
6、说明:增加一个列 hxdjmc-
Alter table tabname add column col type kM-8%a2i
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。 xJ#O|7N
7、说明:添加主键: Alter table tabname add primary key(col) 5X8 i=M;
说明:删除主键: Alter table tabname drop primary key(col) ?taC
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8、说明:创建索引:create [unique] index idxname on tabname(col....) uv5NqL&
删除索引:drop index idxname q'fOlq
注:索引是不可更改的,想更改必须删除重新建。 ^G qO>1U
9、说明:创建视图:create view viewname as select statement xqdkc^b
删除视图:drop view viewname ?Kmz urG
10、说明:几个简单的基本的sql语句 NI/'SMj%
选择:select * from table1 where 范围 @Y,t]
插入:insert into table1(field1,field2) values(value1,value2) Q?hf2iw
删除:delete from table1 where 范围 %#fjtbeB
更新:update table1 set field1=value1 where 范围 ka=A:biz
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 1/bTwzR.g
排序:select * from table1 order by field1,field2 [desc] &R/-~w5
总数:select count as totalcount from table1 qAp<OJ
求和:select sum(field1) as sumvalue from table1 };rEN`L
平均:select avg(field1) as avgvalue from table1 gWro])3
最大:select max(field1) as maxvalue from table1 m,+E5^
最小:select min(field1) as minvalue from table1 :bo2H[U+
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11、说明:几个高级查询运算词 +dCR$<e9r
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A: UNION 运算符 ?gu!P:lZS
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 GQ85ykky
B: EXCEPT 运算符 EId>%0s5
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 Y q/vym-O5
C: INTERSECT 运算符 Gqq<-drR
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 fLRx{Nu
注:使用运算词的几个查询结果行必须是一致的。 N)jNvzm
12、说明:使用外连接 'xEomo#
A、left outer join: (7_ezWSl>
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 m[l&&(+J,
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ao7M([ff
B:right outer join: vh|m[ p
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 y)fz\wk
C:full outer join: )(d~A?~
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 /=V!lRs
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二、提升 z$Z%us>io
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) LvGo$f/9
法一:select * into b from a where 1<>1 "tb KbFn9
法二:select top 0 * into b from a P;7[5HFF
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) od@!WjcM[8
insert into b(a, b, c) select d,e,f from b; * W"Pv,:
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) aA%x9\Y
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 ?y%Mm09
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 3]\'Q}
4、说明:子查询(表名1:a 表名2:b) 3]NKAPY
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) R4D$)D
5、说明:显示文章、提交人和最后回复时间 -R$ Q`Xw
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b Us6~7L00
6、说明:外连接查询(表名1:a 表名2:b) *Qngx
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c %YuFw|wO
7、说明:在线视图查询(表名1:a ) Ug[0l)
select * from (SELECT a,b,c FROM a) T where t.a > 1; [ P*L`F
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 ee<'j~{A
select * from table1 where time between time1 and time2 ?<OE|nb&
select a,b,c, from table1 where a not between 数值1 and 数值2 ](+u'8
9、说明:in 的使用方法 @Rd`/S@
select * from table1 where a [not] in ('值1','值2','值4','值6') ,S}wOjb@
10、说明:两张关联表,删除主表中已经在副表中没有的信息 u#ocx[
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) '*U_!RmQ
11、说明:四表联查问题: _0&U'/cs
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 ..... #pD=TMefC
12、说明:日程安排提前五分钟提醒 .dc|?$XV
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 hZ>1n&[@
13、说明:一条sql 语句搞定数据库分页 ju.`c->k"
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 x {Rj2~KC
14、说明:前10条记录 3E @ &
select top 10 * form table1 where 范围 [8b{Ybaz
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) s2tNQtq0W
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) HS.eK#:N
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 (6)|v S
(select a from tableA ) except (select a from tableB) except (select a from tableC) ^MWp{E
17、说明:随机取出10条数据 *TL3-S?
select top 10 * from tablename order by newid() So NgDFD
18、说明:随机选择记录 W
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select newid() |>JRJ"CFE
19、说明:删除重复记录 E0A[{UA
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) U,<?]h
20、说明:列出数据库里所有的表名 q)"yP\
select name from sysobjects where type='U' M VE:JNm
21、说明:列出表里的所有的 #E/|WT
select name from syscolumns where id=object_id('TableName') 4SkCV
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 0sq?>$~Kc*
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 Z4k'c+
显示结果: (>\4%(pnD
type vender pcs ;M O,HdP;
电脑 A 1 B.?@VF
电脑 A 1 4E$6&,\
光盘 B 2 ?R@u'4yK
光盘 A 2 [L2N[vy;
手机 B 3 f 0/q{*
手机 C 3 _k)EqPYu@
23、说明:初始化表table1 tac_MtW?
TRUNCATE TABLE table1 2"Ki5
24、说明:选择从10到15的记录 BS?rKtdm(
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc _:XX+3W7
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三、技巧 aqP"Y9l
1、1=1,1=2的使用,在SQL语句组合时用的较多 s8*Q@0
"where 1=1" 是表示选择全部 "where 1=2"全部不选, >Qf`xUZ
如: #%/0a
if @strWhere !='' 'V4B{n7h
begin tY`%vI [
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere S8e ?-rC
end YB9)v5Nz(
else kc[<5^b5
begin q$B|a5a?
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' pQCW6X
end Uot LJa
我们可以直接写成 T\TKgO=)
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere aslb^
2、收缩数据库 ~kZ?e1H
--重建索引 DbN_(mC
DBCC REINDEX VpxsgCS
DBCC INDEXDEFRAG c*V/2"
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--收缩数据和日志 F,xFeq$/{
DBCC SHRINKDB 70A* !v
DBCC SHRINKFILE /6'5uP
3、压缩数据库 )4FW~o<i
dbcc shrinkdatabase(dbname) l=>FoJf!*<
4、转移数据库给新用户以已存在用户权限 Pu2cU5n
exec sp_change_users_login 'update_one','newname','oldname' JIMi~mEiN
go V4?]NFK
5、检查备份集 U5;Y o+z
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' LV]F?O[K=
6、修复数据库 qc/)l~]?g{
ALTER DATABASE [dvbbs] SET SINGLE_USER %Xl(wvd
GO NHD`c)Q
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK t|59/R
GO )Q~K\bJf
ALTER DATABASE [dvbbs] SET MULTI_USER E#yG}UWe
GO !h+VbZ
7、日志清除 K^[Dz\ov5
SET NOCOUNT ON _3m\r*(vmQ
DECLARE @LogicalFileName sysname, NvJ}|w,Z
@MaxMinutes INT, oazy%n(KZ
@NewSize INT 'Fa~l'G7X
USE tablename -- 要操作的数据库名 cx+%lco!
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 TxmKmZ u
@MaxMinutes = 10, -- Limit on time allowed to wrap log. RxGZ#!j/
@NewSize = 1 -- 你想设定的日志文件的大小(M) P?M WT]fY
-- Setup / initialize Hg+bmwM
DECLARE @OriginalSize int 8^qLGUxz
SELECT @OriginalSize = size Dp;6CGYl?
FROM sysfiles R5rCCp
WHERE name = @LogicalFileName l7S&s&W @
SELECT 'Original Size of ' + db_name() + ' LOG is ' + +{&++^(}a
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + I*=
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CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' z?g\w6
FROM sysfiles y.WEO>
WHERE name = @LogicalFileName 9y;8JO
CREATE TABLE DummyTrans }N#hg>;
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(DummyColumn char (8000) not null) QzD8
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DECLARE @Counter INT, 'z x1kq1
@StartTime DATETIME, `;3fnTI:1
@TruncLog VARCHAR(255) ()EiBl(kWk
SELECT @StartTime = GETDATE(), b[my5Ol
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' ka| 8 _C^z
DBCC SHRINKFILE (@LogicalFileName, @NewSize) FrQRHbp3
EXEC (@TruncLog) hR~~k~84
-- Wrap the log if necessary. `j(-y`fo
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired uVLKR PY
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) LVNJlRK
AND (@OriginalSize * 8 /1024) > @NewSize K7]+. f
BEGIN -- Outer loop. %g=SkQ&d
SELECT @Counter = 0 _iZ9Ch\
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) Xs$UpQo
BEGIN -- update ~d&W;mef-
INSERT DummyTrans VALUES ('Fill Log') ]t.6bb4
DELETE DummyTrans cp3O$S
SELECT @Counter = @Counter + 1 Aw7_diK^
END u*<knZ~ty
EXEC (@TruncLog) J+f*D+x1
END 7\Wq :<JL
SELECT 'Final Size of ' + db_name() + ' LOG is ' + )\l(h%s[I
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + -i"?2gK
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' f
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FROM sysfiles kPFqsq
WHERE name = @LogicalFileName
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DROP TABLE DummyTrans 6e:#x:O
SET NOCOUNT OFF 76RFu@k
8、说明:更改某个表 {*t0WE&1t
exec sp_changeobjectowner 'tablename','dbo' LVxR*O
9、存储更改全部表 Et+W LQ6)
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 7eQc14
@OldOwner as NVARCHAR(128), y[I)hSD=
@NewOwner as NVARCHAR(128) ^Z:qlYZ
AS *waaM]u
DECLARE @Name as NVARCHAR(128) H4IJLZ3G
DECLARE @Owner as NVARCHAR(128) U9:I"f,
DECLARE @OwnerName as NVARCHAR(128) }^n346^
DECLARE curObject CURSOR FOR n_MY69W
select 'Name' = name, 9*j$U$:'
'Owner' = user_name(uid) [BKX$A:Y
from sysobjects i>=!6Hu2
where user_name(uid)=@OldOwner NT<vs"<B
order by name DjveMs$d
OPEN curObject n 8'#'^|
FETCH NEXT FROM curObject INTO @Name, @Owner
@1O.;
WHILE(@@FETCH_STATUS=0) 45$FcK
BEGIN si`h(VD9w
if @Owner=@OldOwner }ujl2uhM
begin /}#@uC
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ;TTH
exec sp_changeobjectowner @OwnerName, @NewOwner )~H&YINhn
end #Bi8>S
-- select @name,@NewOwner,@OldOwner B0"55g*c
FETCH NEXT FROM curObject INTO @Name, @Owner nypG
END 0XUWK@)P
close curObject y6N }R
deallocate curObject hSF4-Vvb
GO clO9l=g
10、SQL SERVER中直接循环写入数据 h!q_''*;
declare @i int $ {5|{`
set @i=1 !ui:0_
while @i<30 IO}53zn<l
begin ><3!J+<?
insert into test (userid) values(@i) D:vX/mf;7
set @i=@i+1 ~mK|~x01@
end 9 Aq\1QC
小记存储过程中经常用到的本周,本月,本年函数 !OL[1_-4|K
Dateadd(wk,datediff(wk,0,getdate()),-1) U6yZKK
Dateadd(wk,datediff(wk,0,getdate()),6) ud:5_*
Dateadd(mm,datediff(mm,0,getdate()),0) CKr5L
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) dE]yb|Ld
Dateadd(yy,datediff(yy,0,getdate()),0) .<kbYo:MV
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) PQA}_o
上面的SQL代码只是一个时间段 6PdLJ#LS
Dateadd(wk,datediff(wk,0,getdate()),-1) hmM2c15T5
Dateadd(wk,datediff(wk,0,getdate()),6) :~%{
就是表示本周时间段. |.Vs(0O
下面的SQL的条件部分,就是查询时间段在本周范围内的: b,):&M~p
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) IJ#+"(?7,u
而在存储过程中 Auk#pO#
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) (hFyp}jkk
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) $hq'9}ASOL