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。 PK{FQ3b2{
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一、基础 O#8lJ%?
1、说明:创建数据库 X,8Zn06M
CREATE DATABASE database-name _-v$fDrz
2、说明:删除数据库 SBi4i;qD
drop database dbname :<
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3、说明:备份sql server u1z!OofN>
--- 创建 备份数据的 device i3(5
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USE master Z]Z&PbP
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' \`/ P*
--- 开始 备份 fgo3Gy*#
BACKUP DATABASE pubs TO testBack CRzLyiRvU&
4、说明:创建新表 7D8 pb0`;J
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) VqOTrB1w/
根据已有的表创建新表: .v=n-k7
A:create table tab_new like tab_old (使用旧表创建新表) ZWB3R
B:create table tab_new as select col1,col2... from tab_old definition only oq>jCOVh
5、说明:删除新表 eq2LV=d{m
drop table tabname .o<9[d"
6、说明:增加一个列 p[!9 objU
Alter table tabname add column col type 4q@[k:'
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 %N7G>_+
7、说明:添加主键: Alter table tabname add primary key(col) _$}@hD*R~
说明:删除主键: Alter table tabname drop primary key(col) gV5mERKs
8、说明:创建索引:create [unique] index idxname on tabname(col....) tM:$H6m/(
删除索引:drop index idxname S =sL:FC
注:索引是不可更改的,想更改必须删除重新建。 ZM=eiJZ
9、说明:创建视图:create view viewname as select statement
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删除视图:drop view viewname .b2%n;_>.
10、说明:几个简单的基本的sql语句 p Bu}c<
选择:select * from table1 where 范围 ~dsx|G?p
插入:insert into table1(field1,field2) values(value1,value2) [H`5mY@
删除:delete from table1 where 范围 ${t$:0R,h
更新:update table1 set field1=value1 where 范围 ]jmZ5h#[
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! ,mD$h?g
排序:select * from table1 order by field1,field2 [desc] PDh!B_+
总数:select count as totalcount from table1 [S.zWPX9{
求和:select sum(field1) as sumvalue from table1 bGj<Dojl
平均:select avg(field1) as avgvalue from table1 ?U*s H2F
最大:select max(field1) as maxvalue from table1 ufA0H
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最小:select min(field1) as minvalue from table1 gi? wf
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11、说明:几个高级查询运算词 _z"\3hZ
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A: UNION 运算符 Dx P65wU
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。 [s-!tE3-
B: EXCEPT 运算符 iA"H*0
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。 /'>ck2drjk
C: INTERSECT 运算符 V4g vKWc
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。 cyI:dvg
注:使用运算词的几个查询结果行必须是一致的。 WD7T&i
12、说明:使用外连接 g3(?!f
A、left outer join: _ [hVGCSB
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。 @Y6~;(p
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 'sjks sy.3
B:right outer join: 3"6-X_
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。 R
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C:full outer join: ~?lmkfy
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。 #W L>ha
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二、提升 8U-<Q>
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 8{Wh4~|+
法一:select * into b from a where 1<>1 niCq`!
法二:select top 0 * into b from a sQ82(N7l
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) {1vlz>82
insert into b(a, b, c) select d,e,f from b; 73E[O5?b
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) _^w^tfH]
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 X5P1wxk'
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. RJOyPZ]
4、说明:子查询(表名1:a 表名2:b) $0;Dk,
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 Y}Nd2
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b ?uE@C3 e
6、说明:外连接查询(表名1:a 表名2:b) 1ZfhDtK(
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c -s6;IoG/
7、说明:在线视图查询(表名1:a ) $Mqw)X&q
select * from (SELECT a,b,c FROM a) T where t.a > 1;
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8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 .iEzEmu
select * from table1 where time between time1 and time2 |+Ub3<b[]
select a,b,c, from table1 where a not between 数值1 and 数值2 }?%5Ae7l,
9、说明:in 的使用方法 |H-zm&h>'
select * from table1 where a [not] in ('值1','值2','值4','值6') izP>w*/nO
10、说明:两张关联表,删除主表中已经在副表中没有的信息 Y/n],(t)
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 4ko(bW#jL
11、说明:四表联查问题: d-$/C| J
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 ..... Q-f?7*>
12、说明:日程安排提前五分钟提醒 JVNp= ikK
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 8Jf4";
13、说明:一条sql 语句搞定数据库分页 Lc13PTz>>g
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 J]4Uh_>)
14、说明:前10条记录 Jg%jmI;Y
select top 10 * form table1 where 范围 | <l=i(
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.) \@:mq]Y
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) Q|:qs\6q5
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 mA']*)L1
(select a from tableA ) except (select a from tableB) except (select a from tableC) R9lb<`
17、说明:随机取出10条数据 xy1R_*.F^T
select top 10 * from tablename order by newid() *z\L
18、说明:随机选择记录 3 n=ftkI
select newid() XVkCYh4,
19、说明:删除重复记录 SW_jTn#x
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) '#@tovr
20、说明:列出数据库里所有的表名 $n@B:kv5p
select name from sysobjects where type='U' %13V@'e9
21、说明:列出表里的所有的 TbA=bkj[4
select name from syscolumns where id=object_id('TableName') +OC~y:
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 E?[]N[0Kl
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type vmK`QPu2
显示结果: "AUHe6Yv
type vender pcs [}t^+^/
电脑 A 1 &S+ooj
电脑 A 1 /L? ia
光盘 B 2 El#"vIg(\
光盘 A 2 ky-9I<Z,,
手机 B 3 K/ 5U;oC
手机 C 3 i-*ZW:
23、说明:初始化表table1 |KLCO'x
TRUNCATE TABLE table1 8xN+LL'T{
24、说明:选择从10到15的记录 Tg~SGAc
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc mJ L=H
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三、技巧 {<1 ]cP
1、1=1,1=2的使用,在SQL语句组合时用的较多 o6T'U#7P
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ;o-c.-!F
如: 5isqBu
if @strWhere !='' ,37\8y?o\
begin I$w:qS&:
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere YecV+K'p:
end dcbE<W#ss
else {YigB
begin f*46,`x
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' nBJ'ak
end g?i0WS
我们可以直接写成 !rZ r:@
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere [h[@?8vB
2、收缩数据库 vA&MJD{
--重建索引 ?3=y]Vb+
DBCC REINDEX I )wc&>Lc
DBCC INDEXDEFRAG e
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--收缩数据和日志 h 1REL^!c
DBCC SHRINKDB L| K8
DBCC SHRINKFILE 7X`]}z4g
3、压缩数据库 f6k=ew
dbcc shrinkdatabase(dbname) IB\O[R$x
4、转移数据库给新用户以已存在用户权限 $@^*lUw
exec sp_change_users_login 'update_one','newname','oldname' Ev>P|kV&A
go *r(Qy0(
5、检查备份集 ve f9*u`
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' u%sfHGrH
6、修复数据库 l#bE_PD;
ALTER DATABASE [dvbbs] SET SINGLE_USER u1;sH{YK>
GO DA_}pS"
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 9zE/SDu7\
GO uF<}zFS
ALTER DATABASE [dvbbs] SET MULTI_USER jT=fq'RK
GO %fMFcL#h
7、日志清除 MnTJFo"
SET NOCOUNT ON 8@,8j!$8G
DECLARE @LogicalFileName sysname, )}lO%B'K
@MaxMinutes INT, <%?!3 n*
@NewSize INT %sCG}?
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USE tablename -- 要操作的数据库名 A9Icn>3?`(
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ~CuJ$(9Y
@MaxMinutes = 10, -- Limit on time allowed to wrap log. [P*zm 8b
@NewSize = 1 -- 你想设定的日志文件的大小(M) TpcJ1*t
-- Setup / initialize Pl\NzB,`
DECLARE @OriginalSize int ]FEDAGu
SELECT @OriginalSize = size 8_/,`}9
FROM sysfiles unc8WXW
WHERE name = @LogicalFileName (;9j#x
SELECT 'Original Size of ' + db_name() + ' LOG is ' + @%BsQm
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + IoZ_zz0
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' {t!Pv2y<
FROM sysfiles r;_*.|AH
WHERE name = @LogicalFileName 0+T:};]
CREATE TABLE DummyTrans Yk0/f|>O
(DummyColumn char (8000) not null) =[,EFkU?B
DECLARE @Counter INT, lYT_Y.%I
@StartTime DATETIME, <:4b4Nl
@TruncLog VARCHAR(255) dkg|
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SELECT @StartTime = GETDATE(), vj9'5]!~q
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' |3 mcL'
DBCC SHRINKFILE (@LogicalFileName, @NewSize) {Z1KU8tp
EXEC (@TruncLog) dU-nE5
-- Wrap the log if necessary. nK}-^Ur
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired
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AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) OwPXQ 3S
AND (@OriginalSize * 8 /1024) > @NewSize N}nE?|N=5
BEGIN -- Outer loop. 5mX^{V&^
SELECT @Counter = 0 ?&!e
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WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) i.{.koH<
BEGIN -- update 3&6sQ-}*
INSERT DummyTrans VALUES ('Fill Log') "U/yq
DELETE DummyTrans =IKgi-l*
SELECT @Counter = @Counter + 1 <G'M/IR a
END a"l\_D'.K8
EXEC (@TruncLog) +8Y|kC{9"
END a(kY,<}
SELECT 'Final Size of ' + db_name() + ' LOG is ' + nk;^sq4M:
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + TKQ^D
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' `{m,&[n
FROM sysfiles ~~=]_lwyK%
WHERE name = @LogicalFileName /P Tq.
DROP TABLE DummyTrans zp5ZZcj_
SET NOCOUNT OFF q\-P/aN_
8、说明:更改某个表 ksTK'7*
exec sp_changeobjectowner 'tablename','dbo' |AT`(71
9、存储更改全部表 `X)A$lLr
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 'rTJ*1i
@OldOwner as NVARCHAR(128), W23Q>x&S
@NewOwner as NVARCHAR(128) [jksOC)@4
AS N.0g%0A.D
DECLARE @Name as NVARCHAR(128) y` {|D*
DECLARE @Owner as NVARCHAR(128) @AM11v\:
DECLARE @OwnerName as NVARCHAR(128) e)N<r
DECLARE curObject CURSOR FOR +z:>Nl
select 'Name' = name, /4N ?v. jf
'Owner' = user_name(uid) +prUau*
from sysobjects ns*:mGh
where user_name(uid)=@OldOwner #SG.`J<%
order by name dS\!tdHP-Q
OPEN curObject -2(?O`tZ
FETCH NEXT FROM curObject INTO @Name, @Owner IMBjI#\
WHILE(@@FETCH_STATUS=0) R1/c@HQw?
BEGIN =XK}eQ_d
if @Owner=@OldOwner i"xV=.
begin ,FXc_BCx4
set @OwnerName = @OldOwner + '.' + rtrim(@Name) !zvOCAb,
exec sp_changeobjectowner @OwnerName, @NewOwner K|l}+:k
end *[m:4\
-- select @name,@NewOwner,@OldOwner _]- 4UA-
FETCH NEXT FROM curObject INTO @Name, @Owner I9Uj3cL\
END G&@dJ &B
close curObject QBG jH^kL
deallocate curObject I ~^Xw7
GO .YWkFTlZ+
10、SQL SERVER中直接循环写入数据 !v(^wqna\
declare @i int (
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set @i=1 00{a}@n
while @i<30 B:Ft(,
begin a
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insert into test (userid) values(@i) _aBy>=2c$
set @i=@i+1 u!&T}i:
end 5423Ky<
小记存储过程中经常用到的本周,本月,本年函数 wlsx|
Dateadd(wk,datediff(wk,0,getdate()),-1) ;^u,[d
Dateadd(wk,datediff(wk,0,getdate()),6) _C(fz CK
Dateadd(mm,datediff(mm,0,getdate()),0) :U *8S\$
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) lSlZ^.&
Dateadd(yy,datediff(yy,0,getdate()),0) a+\<2NXYD
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 5ba e-
上面的SQL代码只是一个时间段 >MSK.SNh
Dateadd(wk,datediff(wk,0,getdate()),-1) >*opE I+
Dateadd(wk,datediff(wk,0,getdate()),6) Qc)i?Z'6
就是表示本周时间段. Dy>6L79G
下面的SQL的条件部分,就是查询时间段在本周范围内的: Jm#p!G+
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) c~O
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而在存储过程中 TUz4-Pd
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) M@P%k`6C
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) {Z7ixc523