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。 g)p[A 4
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一、基础 }oU&J81
1、说明:创建数据库 ~~fL`"
CREATE DATABASE database-name WYzY#-j
2、说明:删除数据库 e4`KnHsL
drop database dbname Xs?>6i@$$
3、说明:备份sql server rU~"A
--- 创建 备份数据的 device GYs4#40
USE master jyT(LDsS
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' VI+Y 4T@
--- 开始 备份 EwOTG
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BACKUP DATABASE pubs TO testBack {MEU|9@
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4、说明:创建新表 d[Fsp7U}
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 'V>+G>U
根据已有的表创建新表: d
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A:create table tab_new like tab_old (使用旧表创建新表) 2'}2r ~6
B:create table tab_new as select col1,col2... from tab_old definition only =VSieh
5、说明:删除新表 s3knh&'zb
drop table tabname 02+^rqIx5
6、说明:增加一个列 r-0
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Alter table tabname add column col type ){(cRB $
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。 Ud9\;Qse
7、说明:添加主键: Alter table tabname add primary key(col) ]E3g8?L
说明:删除主键: Alter table tabname drop primary key(col) AP~!YwLW
8、说明:创建索引:create [unique] index idxname on tabname(col....) ;s!H
删除索引:drop index idxname bQ4 }no0
注:索引是不可更改的,想更改必须删除重新建。 ujSzm=_P
9、说明:创建视图:create view viewname as select statement |JDJ{;o
删除视图:drop view viewname nbRg<@
10、说明:几个简单的基本的sql语句 TDseWdA
选择:select * from table1 where 范围 DxD0iJ=W
插入:insert into table1(field1,field2) values(value1,value2) FG(`&S+,
删除:delete from table1 where 范围 d+w<y~\
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更新:update table1 set field1=value1 where 范围 jGWLYI=V2
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 3z ry %qV=
排序:select * from table1 order by field1,field2 [desc] BA5= D>T-
总数:select count as totalcount from table1 ~iSW^mi
求和:select sum(field1) as sumvalue from table1 axl?t|~I
平均:select avg(field1) as avgvalue from table1 +Q9HsfX/
最大:select max(field1) as maxvalue from table1
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最小:select min(field1) as minvalue from table1 0jS/U|0
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11、说明:几个高级查询运算词 LH8?0N[
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A: UNION 运算符 \X`P
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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。 ^
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B: EXCEPT 运算符
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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*A `M
C: INTERSECT 运算符 kr/h^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。 loB/w{r*x
注:使用运算词的几个查询结果行必须是一致的。 WI9.?(5q
12、说明:使用外连接 7l p VK]
A、left outer join: u rOG Oa$
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。 .G]# _U
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 gdT_kb5HL8
B:right outer join: vP2QAGk<
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。 !L_ SHlU
C:full outer join: uj@<_|7
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。
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二、提升 2uTa}{/%
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) ww2Qa-K
法一:select * into b from a where 1<>1 bi[l ,
法二:select top 0 * into b from a q ha1b$
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) {P5@2u6S
insert into b(a, b, c) select d,e,f from b; m0,9yY::wj
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) `lhLIQ'j
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 <j#EyGAV
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. -T8
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4、说明:子查询(表名1:a 表名2:b) 1sJN^BvuG
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) lN'/Z&62
5、说明:显示文章、提交人和最后回复时间 ""d>f4,S
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 7y\g~?5N
6、说明:外连接查询(表名1:a 表名2:b) a*hThr+$M
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c X
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7、说明:在线视图查询(表名1:a ) "=(;l3-o
select * from (SELECT a,b,c FROM a) T where t.a > 1; {Jc!T:vJ
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 aiHr2x6
select * from table1 where time between time1 and time2 #V6
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select a,b,c, from table1 where a not between 数值1 and 数值2 m5pVt4
9、说明:in 的使用方法 w-$w
select * from table1 where a [not] in ('值1','值2','值4','值6') *PEuaRDN
10、说明:两张关联表,删除主表中已经在副表中没有的信息 pYG,5+g
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) *
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11、说明:四表联查问题: bAiw]xi
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 ..... O m
12、说明:日程安排提前五分钟提醒 q9!9OcN2
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 l/^-:RRNKi
13、说明:一条sql 语句搞定数据库分页 A&F4;>dms
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 Y
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14、说明:前10条记录 mmL~`i/
select top 10 * form table1 where 范围 ;Y^RF?un
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.) <^Tj}5)n
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) m #QI*R
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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 *F*X_O
(select a from tableA ) except (select a from tableB) except (select a from tableC) ;%<4U^2
17、说明:随机取出10条数据 Y ,yaB)&Ih
select top 10 * from tablename order by newid() m-RY{DO+
18、说明:随机选择记录 Ji[g@#
select newid() g-FZel
19、说明:删除重复记录 Ak Tw?v'
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) cloI 6%5r
20、说明:列出数据库里所有的表名 ~PnpYd<2
select name from sysobjects where type='U' EC'bgFe
21、说明:列出表里的所有的 uN
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select name from syscolumns where id=object_id('TableName') %Z yPK,("
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。 1,QZnF!.x
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 29^bMau)v
显示结果: 3L?a4,Q"k}
type vender pcs GuWBl$|+b
电脑 A 1 Ba0D"2CgY
电脑 A 1 yXx62J
光盘 B 2 e,&%Z
光盘 A 2 bOMP8{H,
手机 B 3 sjgR \`AU
手机 C 3 0
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23、说明:初始化表table1 MPn>&28"|K
TRUNCATE TABLE table1 |:+pPh!-
24、说明:选择从10到15的记录 i(;-n_:,`
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc %n25Uq
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三、技巧 q&Wwtqc9
1、1=1,1=2的使用,在SQL语句组合时用的较多 X&.$/xaT
"where 1=1" 是表示选择全部 "where 1=2"全部不选, [!?,TGM}^
如: -/c1qLdQ
if @strWhere !='' 0t?<6-3`/
begin K=TW}ZO
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere Z(mn
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end O^weUpe\
else N>%KV8>{L
begin T1HiHvJ
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' g/Jj]X#r
end cGta4;
我们可以直接写成 $L8s/1up
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere K)UOx#xe1
2、收缩数据库 "!6~*!]c
--重建索引 8M+F!1-#
DBCC REINDEX xKST-:c +
DBCC INDEXDEFRAG P=[x!}.I
--收缩数据和日志 14 'x-w^~k
DBCC SHRINKDB up3<=u{>
DBCC SHRINKFILE ysJhP .
3、压缩数据库 C$G88hesn
dbcc shrinkdatabase(dbname) Q
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4、转移数据库给新用户以已存在用户权限 L_ qv<iM$
exec sp_change_users_login 'update_one','newname','oldname' 6XL9
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go 1vK(^u[
5、检查备份集 G!LNP&~
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' j_uY8c>3\q
6、修复数据库 PB<Sc>{U
ALTER DATABASE [dvbbs] SET SINGLE_USER N|d.!Q;V.y
GO a 8hv .43
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK n;^k
GO 7W firRM
ALTER DATABASE [dvbbs] SET MULTI_USER 9Q7cUoxY
GO `[ ` *@O(y
7、日志清除 | ,l=v`/
SET NOCOUNT ON sFM>gG
DECLARE @LogicalFileName sysname, [-Tt11
@MaxMinutes INT, %802H%+
@NewSize INT YZ:'8<
USE tablename -- 要操作的数据库名 h9w^7MbO
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 wQrPS
@MaxMinutes = 10, -- Limit on time allowed to wrap log. ?Gv!d
@NewSize = 1 -- 你想设定的日志文件的大小(M) `)!2E6 =
-- Setup / initialize us,,W(q
DECLARE @OriginalSize int 9
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SELECT @OriginalSize = size C\2 >7
FROM sysfiles UFAMbI
WHERE name = @LogicalFileName hPi
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SELECT 'Original Size of ' + db_name() + ' LOG is ' + P}WhE
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + X`v79`g_
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' X1V}%@3:
FROM sysfiles MN M>
WHERE name = @LogicalFileName ]#-/i2-K
CREATE TABLE DummyTrans i2}=/
(DummyColumn char (8000) not null) 5A]LNA4i
DECLARE @Counter INT, f+aS2k(e>
@StartTime DATETIME, Ta\8>\6
@TruncLog VARCHAR(255) 9Glfi@.
SELECT @StartTime = GETDATE(), Ysc|kxLb
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' '"fU2M<.
DBCC SHRINKFILE (@LogicalFileName, @NewSize) nP{sCH 1
EXEC (@TruncLog) tTh;.88Z{
-- Wrap the log if necessary. 0CVsDVA
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired \%?8jQ'tX
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 7- 3N
AND (@OriginalSize * 8 /1024) > @NewSize ocA'goI-
BEGIN -- Outer loop. z'}= A
SELECT @Counter = 0 c;8"vJ
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) -f;j1bQ
BEGIN -- update K-Dk2(x
INSERT DummyTrans VALUES ('Fill Log') sa gBmA~
DELETE DummyTrans s?;<F
SELECT @Counter = @Counter + 1 {{[jC"4AY
END ic{.#R.BY
EXEC (@TruncLog) &0
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END -G<2R"Q#N
SELECT 'Final Size of ' + db_name() + ' LOG is ' + )av'u.]%c
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + IU'!?XVo
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' N"
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FROM sysfiles iI@Gyq=
WHERE name = @LogicalFileName am'p^Z@
DROP TABLE DummyTrans pGbFg&
SET NOCOUNT OFF v!{'23`87
8、说明:更改某个表 CMxjX
exec sp_changeobjectowner 'tablename','dbo' qfP"UAc{/
9、存储更改全部表 .";tnC!e
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch E
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@OldOwner as NVARCHAR(128), xX&>5 "
@NewOwner as NVARCHAR(128) SL\y\GaV
AS ?ZuD
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DECLARE @Name as NVARCHAR(128) lF}$`6
DECLARE @Owner as NVARCHAR(128) i h$@:^\
DECLARE @OwnerName as NVARCHAR(128) vPl6Dasr
DECLARE curObject CURSOR FOR WVT5VJ7*
select 'Name' = name, ug6f
'Owner' = user_name(uid) tp0!,ne*
from sysobjects K.iH
where user_name(uid)=@OldOwner Yr"!&\[oz
order by name q{De&Bu
OPEN curObject &b@!DAwAJ
FETCH NEXT FROM curObject INTO @Name, @Owner k.=S+#"}
WHILE(@@FETCH_STATUS=0) (|a$N.e&K
BEGIN x+*L5$;h
if @Owner=@OldOwner Xv7U<q
begin Puth8$
set @OwnerName = @OldOwner + '.' + rtrim(@Name) gcW{]0%L^
exec sp_changeobjectowner @OwnerName, @NewOwner K@j^gF/0B
end N9JgV,`
-- select @name,@NewOwner,@OldOwner Xx y
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FETCH NEXT FROM curObject INTO @Name, @Owner & L.PU@
END _^xh1=Qr}n
close curObject |p8"9jN@}c
deallocate curObject {sfmWVp
GO il>x!)?o
10、SQL SERVER中直接循环写入数据 i^s`6:rNu
declare @i int ghJ,s|lH
set @i=1 9?l?G GmQ
while @i<30 (4{ C7
begin srChY&h?<
insert into test (userid) values(@i) ll<9f)
set @i=@i+1 z7t'6Fy9'
end ;oY(I7
小记存储过程中经常用到的本周,本月,本年函数 s7UhC.>'@
Dateadd(wk,datediff(wk,0,getdate()),-1) JJ
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Dateadd(wk,datediff(wk,0,getdate()),6) k qY3r &
Dateadd(mm,datediff(mm,0,getdate()),0) I"F
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Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ><#2O
Dateadd(yy,datediff(yy,0,getdate()),0) CNpe8M=/3
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) .^W\OJ`G
上面的SQL代码只是一个时间段 (Xr_ np @
Dateadd(wk,datediff(wk,0,getdate()),-1) y[^k*,=
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Dateadd(wk,datediff(wk,0,getdate()),6) /50g3?X,
就是表示本周时间段. .n)!ZN
下面的SQL的条件部分,就是查询时间段在本周范围内的: az\<sWb#
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) S-M)MCL
而在存储过程中 =mi:<q
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) aX[1H6&=7
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) x'=3&vc4