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。 :dq.@:+<R
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一、基础 [p3{d\=*?
1、说明:创建数据库 uP, iGA
CREATE DATABASE database-name (
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2、说明:删除数据库 :B{Wf 2<z
drop database dbname lC/1,Z/M
3、说明:备份sql server 3}aKok"k
--- 创建 备份数据的 device ?+av9;Kg
USE master %jk7JDvl
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' K+MSjQS"
--- 开始 备份 r5 tn'
BACKUP DATABASE pubs TO testBack -fpe
4、说明:创建新表 WoM;) Q
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) -]el_:H
根据已有的表创建新表: ]l4\Tdz
A:create table tab_new like tab_old (使用旧表创建新表) 9$[6\jMh
B:create table tab_new as select col1,col2... from tab_old definition only %O6r
5、说明:删除新表 LNp{lC
drop table tabname "Vh3hnS~
6、说明:增加一个列 A,67)li3
Alter table tabname add column col type GsIVx!
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。 6_|iXs(&
7、说明:添加主键: Alter table tabname add primary key(col) z^lcc7
说明:删除主键: Alter table tabname drop primary key(col) `#HtVI
8、说明:创建索引:create [unique] index idxname on tabname(col....) +t*V7nW
删除索引:drop index idxname ebno:)
注:索引是不可更改的,想更改必须删除重新建。 /2^"c+/'p
9、说明:创建视图:create view viewname as select statement ;)~}/nR<a
删除视图:drop view viewname PAng(tubl
10、说明:几个简单的基本的sql语句 8tfM,.]_i
选择:select * from table1 where 范围 &O
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插入:insert into table1(field1,field2) values(value1,value2) /tm2b<G
删除:delete from table1 where 范围 >~@O\n-t
更新:update table1 set field1=value1 where 范围 $7h]A$$Fv
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! !/nXEjW?
排序:select * from table1 order by field1,field2 [desc] OfG/7pw5%B
总数:select count as totalcount from table1 SR%k|YT
求和:select sum(field1) as sumvalue from table1 riR(CJ}Ff
平均:select avg(field1) as avgvalue from table1 @)#EZQi x
最大:select max(field1) as maxvalue from table1 YRg"{[+#]k
最小:select min(field1) as minvalue from table1 <OY (y#x
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11、说明:几个高级查询运算词 /H4Z.|@
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A: UNION 运算符 9|D*}OY>
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。 e5RF6roxO
B: EXCEPT 运算符 I(<9e"1O
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。 !3F3E8%
C: INTERSECT 运算符 :@uIEvD?
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。 (1EtC{
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注:使用运算词的几个查询结果行必须是一致的。 6VUs:iO1j5
12、说明:使用外连接 KH$|wv
A、left outer join: s&hJ[$i
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。 E1r-$gf_
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c }7non
B:right outer join: b5Q|$E
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。 hrNB"W|?x
C:full outer join: GYZP?E p*
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。 f=k_U[b4>
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二、提升 JDJ"D\85
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) TAxu ]C$P
法一:select * into b from a where 1<>1 3Fb9\2<H
法二:select top 0 * into b from a \sBXS.
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) N5[^W`Qf
insert into b(a, b, c) select d,e,f from b; HQvJ*U4++
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) 6Hbu7r*tm
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 g,9&@g/
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 3
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4、说明:子查询(表名1:a 表名2:b) }u9#S
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) NnH]c+
5、说明:显示文章、提交人和最后回复时间 "1YwV~M5
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b >?Duz+W)
6、说明:外连接查询(表名1:a 表名2:b) VV;%q3}:
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c Rk,'ujc
7、说明:在线视图查询(表名1:a ) beaSvhPU
select * from (SELECT a,b,c FROM a) T where t.a > 1; ({ O~O5k
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 O8OAXRt/Y
select * from table1 where time between time1 and time2 e2e!"kEF
select a,b,c, from table1 where a not between 数值1 and 数值2 ;FQNO:NP
9、说明:in 的使用方法 9X?RJ."J
select * from table1 where a [not] in ('值1','值2','值4','值6') bwM?DY
10、说明:两张关联表,删除主表中已经在副表中没有的信息 ]]0Yh
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) PYBE?td
11、说明:四表联查问题: 2E8G5?qe)
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 ..... He,,bq
12、说明:日程安排提前五分钟提醒 @R-11wP)M
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ZNVrja*
13、说明:一条sql 语句搞定数据库分页 qJ sH
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 -Bl]RpHCe
14、说明:前10条记录 It7R}0Smg
select top 10 * form table1 where 范围 ,Nt^$2DZW
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) t~7OtPF
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) (dfC}x(3h
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 'W,*mfB
(select a from tableA ) except (select a from tableB) except (select a from tableC) j7U&a}(
17、说明:随机取出10条数据
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select top 10 * from tablename order by newid() M^*\$K%
18、说明:随机选择记录 Esu{c9,
select newid() tLi91)oG
19、说明:删除重复记录 g<@Q)p*ow
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) lb$_$+@Vr
20、说明:列出数据库里所有的表名 GE`1j'^-
select name from sysobjects where type='U' &|j0GP&
21、说明:列出表里的所有的 3&>0'h
select name from syscolumns where id=object_id('TableName') Y)@Y$_
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。 J5(0J7C
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 iciKjXJ:
显示结果: 4Q/{lqG
type vender pcs |h}4J
电脑 A 1 \-pqqSy
电脑 A 1 IU<lF) PF$
光盘 B 2 #}Yrxf
光盘 A 2 J%-4ZB"
手机 B 3 m}u)C&2>
手机 C 3 q}+zNeC
23、说明:初始化表table1 %ufh
TRUNCATE TABLE table1 NT0n[o^
24、说明:选择从10到15的记录 ]J [d8S5
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc Th$Z9+()
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三、技巧 OLPY<ax
1、1=1,1=2的使用,在SQL语句组合时用的较多 $[}EV(#y
"where 1=1" 是表示选择全部 "where 1=2"全部不选, F~i ~%f,
如: 4(sHUWT
if @strWhere !='' JO`r)_
begin J$sBfOD
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere ~+j2a3rv-{
end 1
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else PWZd<
begin =6qTz3t
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' UOsK(mB
end &&m3E=K!^
我们可以直接写成 rrr_{d/
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere d|oO2yzWv
2、收缩数据库 ]/kpEx
--重建索引 ]iGeqwT
DBCC REINDEX ;1[Z&Uv8
DBCC INDEXDEFRAG R|}N"J _
--收缩数据和日志 1cv~_jFh
DBCC SHRINKDB gs;^SRE I
DBCC SHRINKFILE 0Dna+V/jI
3、压缩数据库 J,:&U
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dbcc shrinkdatabase(dbname) y] c1x=x
4、转移数据库给新用户以已存在用户权限 hVmnXT
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exec sp_change_users_login 'update_one','newname','oldname' t"Ci1"U
go En1LGi4#
5、检查备份集 X3a 9-
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 'prHXzi(h
6、修复数据库 (De{r|
ALTER DATABASE [dvbbs] SET SINGLE_USER /zt M'
GO j{YYG|
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK xI1{Wo*2C}
GO c\2rKqFD8
ALTER DATABASE [dvbbs] SET MULTI_USER n8F~!|lQ0
GO k'PvTWR
7、日志清除 Lj(cCtb)
SET NOCOUNT ON |mE;HvQF
DECLARE @LogicalFileName sysname, h Fik>B#!
@MaxMinutes INT, 0W}qp?
@NewSize INT ghWWJx9
USE tablename -- 要操作的数据库名 %2T
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SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 h#"$W;(
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 7]xDMu'^&f
@NewSize = 1 -- 你想设定的日志文件的大小(M) R?O)vLmd
-- Setup / initialize ^l|b>z"0ao
DECLARE @OriginalSize int B Z|A&;
SELECT @OriginalSize = size 1Vdi5;dn
FROM sysfiles F'b%D
WHERE name = @LogicalFileName y7M{L8{0
SELECT 'Original Size of ' + db_name() + ' LOG is ' + z,4mg6gt
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + sa4w.9O1GS
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' J6n>{iE
FROM sysfiles s6@mXO:H^
WHERE name = @LogicalFileName HB8s[]A:D
CREATE TABLE DummyTrans l@Vv%w9H
(DummyColumn char (8000) not null) uyxYCc
DECLARE @Counter INT, 7Vsp<s9bj
@StartTime DATETIME, R`cP%7K
@TruncLog VARCHAR(255) o(oOB
SELECT @StartTime = GETDATE(), a3<:F2=~\
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 2^=.j2
DBCC SHRINKFILE (@LogicalFileName, @NewSize) z'"7zLQ
EXEC (@TruncLog) q:/df]Ntt
-- Wrap the log if necessary. 4lB??`UN
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 8rH6L:]S
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 8{!d'Pks
AND (@OriginalSize * 8 /1024) > @NewSize }a||@unr
BEGIN -- Outer loop. -p&u=
SELECT @Counter = 0 d(o=)!p
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) A}SGw.3
BEGIN -- update PQkw)D<n]_
INSERT DummyTrans VALUES ('Fill Log') ve
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DELETE DummyTrans \jtA8o%n
SELECT @Counter = @Counter + 1 Os@b8V 8,A
END Fs( PVN
EXEC (@TruncLog) nf/?7~3?[
END b/'c
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + ZrTB%
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + X+aQ 7^"s
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' \]V:>=ry>
FROM sysfiles C~B ]@xxK)
WHERE name = @LogicalFileName GYfOwV!zB
DROP TABLE DummyTrans [|OII!"
SET NOCOUNT OFF teg5g|*
8、说明:更改某个表 HCs^?s8Pp
exec sp_changeobjectowner 'tablename','dbo' gHLI>ew*QR
9、存储更改全部表 JP5e=Z<
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch E(P
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@OldOwner as NVARCHAR(128), PlGif)
@NewOwner as NVARCHAR(128) /ooGyF
AS >\Dy
DECLARE @Name as NVARCHAR(128) -!Myw&*\V
DECLARE @Owner as NVARCHAR(128) 93HVx#
DECLARE @OwnerName as NVARCHAR(128) P>C'?'Q7
DECLARE curObject CURSOR FOR e~SK*vR%]
select 'Name' = name, Nnl3r@
'Owner' = user_name(uid) YpDJ(61+
from sysobjects z6iKIw
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where user_name(uid)=@OldOwner RW L0@\
order by name ]=00<~ l*q
OPEN curObject y4Jc|)
FETCH NEXT FROM curObject INTO @Name, @Owner I_ mus<sE
WHILE(@@FETCH_STATUS=0) IC0L&;En
BEGIN @gD)pH
if @Owner=@OldOwner {*7MT}{(
begin Ai<
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set @OwnerName = @OldOwner + '.' + rtrim(@Name) wQ/* f9
exec sp_changeobjectowner @OwnerName, @NewOwner 3F2IL)Hn
end sgp.;h'
-- select @name,@NewOwner,@OldOwner 'RMUjJ-!
FETCH NEXT FROM curObject INTO @Name, @Owner WR)=VE
END ^)Hf%
close curObject Plp.\N%f3
deallocate curObject N&NBn(
GO /l*v *tl
10、SQL SERVER中直接循环写入数据 ^HSxE
declare @i int @.e X8~3=
set @i=1 R&Y_
while @i<30 _J
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begin ~?F,kmO}?
insert into test (userid) values(@i) OoSk^U)
set @i=@i+1 ,-#MEr
end mVZh_R=a
小记存储过程中经常用到的本周,本月,本年函数 x%}D+2ro-t
Dateadd(wk,datediff(wk,0,getdate()),-1) u#@/^h;
Dateadd(wk,datediff(wk,0,getdate()),6) W`;;fJe
Dateadd(mm,datediff(mm,0,getdate()),0) kh
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Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) zeHF-_{
Dateadd(yy,datediff(yy,0,getdate()),0) !%G]~
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 7Jf~Bn
上面的SQL代码只是一个时间段 D~6[C:m
Dateadd(wk,datediff(wk,0,getdate()),-1) %e E^Y<@g
Dateadd(wk,datediff(wk,0,getdate()),6) |h]V9=
就是表示本周时间段. tK%ie\
下面的SQL的条件部分,就是查询时间段在本周范围内的: fjRVYOG#
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) '47
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而在存储过程中 !DZ=`a?y
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) UX)GA[WI
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) #d-({blo<