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。 r'd/qnd
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一、基础 P^(.tr3t
1、说明:创建数据库 z~.9@[LG]
CREATE DATABASE database-name 5<N~3
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2、说明:删除数据库 +k
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drop database dbname l10-XU02
3、说明:备份sql server *g$agyOfh
--- 创建 备份数据的 device X')S;KW
USE master 1NGyaI
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ~'[jBn)
--- 开始 备份 3M$X:$b
BACKUP DATABASE pubs TO testBack X2P``YFV{
4、说明:创建新表 {_as!5l
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) B"[{]GP BY
根据已有的表创建新表: bm6hZA|
A:create table tab_new like tab_old (使用旧表创建新表) <_f`$z
B:create table tab_new as select col1,col2... from tab_old definition only vXf:~G]
5、说明:删除新表 (txt8q
drop table tabname 08io<c,L
6、说明:增加一个列 *+~D+_,
Alter table tabname add column col type ^;64!BaK
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。 ;o%:7&
7、说明:添加主键: Alter table tabname add primary key(col) IQoH@l&Xk
说明:删除主键: Alter table tabname drop primary key(col) sU*3\
8、说明:创建索引:create [unique] index idxname on tabname(col....) UKYupLu5
删除索引:drop index idxname Zsk?QS FE
注:索引是不可更改的,想更改必须删除重新建。 s*+ZYPk
9、说明:创建视图:create view viewname as select statement /h-6CR
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删除视图:drop view viewname tGqQJT#mr7
10、说明:几个简单的基本的sql语句 54wM8'+
选择:select * from table1 where 范围 4ac1m,Jlt
插入:insert into table1(field1,field2) values(value1,value2) FpC~1Nau
删除:delete from table1 where 范围 k -]xSKG
更新:update table1 set field1=value1 where 范围 f MzYFM'i
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! y&3TQ]f\
排序:select * from table1 order by field1,field2 [desc] %/md"S
总数:select count as totalcount from table1 r8+*|$K
求和:select sum(field1) as sumvalue from table1 )(.%QSA\C
平均:select avg(field1) as avgvalue from table1 X}?ESjZJ
最大:select max(field1) as maxvalue from table1 IrUi
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最小:select min(field1) as minvalue from table1 {DS\!0T-X
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11、说明:几个高级查询运算词 X{s/``n
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A: UNION 运算符 1>yha
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UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 taixBNv
B: EXCEPT 运算符 Z]p8IH%~92
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 v0u\xX[H;
C: INTERSECT 运算符 !`Xt8q\r
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 oc =tI@W
注:使用运算词的几个查询结果行必须是一致的。 hOl=W |)v
12、说明:使用外连接 `:R-[>5P8
A、left outer join: ?.~]mvOR
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 bWUS9WT
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c
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B:right outer join: Gzj3Ka
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 &R0OeRToUb
C:full outer join: ;h~?ko
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 LEA;dSf
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二、提升 T[m ~6
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) Q{8qm<0g
法一:select * into b from a where 1<>1 SUo^c1)G
法二:select top 0 * into b from a rEg+i@~
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) <gR`)YF7
insert into b(a, b, c) select d,e,f from b; 8 `o{b"l+
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) C*$|#.l
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 V!H(;Tuuo
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. ]}/mFY?7
4、说明:子查询(表名1:a 表名2:b) |o|gP8
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) z,M'Tr.1|
5、说明:显示文章、提交人和最后回复时间 n~9 i^
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b GPMrs)J*!
6、说明:外连接查询(表名1:a 表名2:b) tb:
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c _,t&C7Yf;
7、说明:在线视图查询(表名1:a ) BjwMb&a;
select * from (SELECT a,b,c FROM a) T where t.a > 1; $}V7(wu 6@
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 TJE%
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select * from table1 where time between time1 and time2 {$3j/b
select a,b,c, from table1 where a not between 数值1 and 数值2 JUmw$u
9、说明:in 的使用方法 m&,bC)}
select * from table1 where a [not] in ('值1','值2','值4','值6') zU=YNrn
10、说明:两张关联表,删除主表中已经在副表中没有的信息 Th_Q
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delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) oEN)Dw
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11、说明:四表联查问题: |x*{fXdMhr
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 ..... nD(w @c?
12、说明:日程安排提前五分钟提醒 TS/Cp{
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ~@[(U!G
13、说明:一条sql 语句搞定数据库分页 hyM'x*
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 F
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14、说明:前10条记录 _`slkwP.
select top 10 * form table1 where 范围 i1tVdbC]
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.) bx;yHIRb
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ?VUgwP_=
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 ,9F*96
(select a from tableA ) except (select a from tableB) except (select a from tableC) uAc@ Z-
17、说明:随机取出10条数据 }7-7t{G
select top 10 * from tablename order by newid() e21E_exM0
18、说明:随机选择记录 &3jBE--
select newid() Lf[G>0t&n
19、说明:删除重复记录 !-F ^VGD(8
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) te4F"SEf
20、说明:列出数据库里所有的表名 /A0 [_
select name from sysobjects where type='U' U0!^m1U:
21、说明:列出表里的所有的 0`V3s]%iu
select name from syscolumns where id=object_id('TableName') LG"c8Vv&)~
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。 mu 2
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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 \nrgAC-b
显示结果:
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type vender pcs hEVjeC
电脑 A 1 bcUC4g\9N
电脑 A 1 t1G1(F#&%
光盘 B 2 "w(N62z/
光盘 A 2 83\o(
手机 B 3 @X3 gBGY)
手机 C 3 2f`WDL
23、说明:初始化表table1 nXv 7OEpTx
TRUNCATE TABLE table1 w/?nUp
24、说明:选择从10到15的记录 lv=yz\
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc X!HDj<
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三、技巧 14mXx}O
1、1=1,1=2的使用,在SQL语句组合时用的较多 /#:Rd^
"where 1=1" 是表示选择全部 "where 1=2"全部不选, R.91v4J
如: Y')O>C0~
if @strWhere !='' TP{>O%b
begin S`ax*`
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 'bZMh9|
end YgO aZqN
else *?EO n -
begin fG X1y
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' \Oi5=,
end #> 7')G
我们可以直接写成 pg}~vb"
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere V?U%C%C|e
2、收缩数据库 =Jsg{vI
--重建索引 <$RS*n
DBCC REINDEX
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DBCC INDEXDEFRAG jl;kcGE
--收缩数据和日志 N$N;Sw
DBCC SHRINKDB #H'sZv
DBCC SHRINKFILE "Czz,;0
3、压缩数据库 Es.toOH$S
dbcc shrinkdatabase(dbname) 73'U#@g6
4、转移数据库给新用户以已存在用户权限 R4&|t
exec sp_change_users_login 'update_one','newname','oldname' 3*CzXK>`M&
go 7JxE|G
5、检查备份集 Z}sG3p
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' d9`3EP)n
6、修复数据库 1mT|o_K{ T
ALTER DATABASE [dvbbs] SET SINGLE_USER ~C}(\8g
GO ?2JS&i
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK z*Myokhf
GO 9\AEyaJFZ
ALTER DATABASE [dvbbs] SET MULTI_USER 7$g*N6)Q
GO ^U-vD[O8
7、日志清除 Ymwx(Pm
SET NOCOUNT ON Sf+(1_^`t
DECLARE @LogicalFileName sysname, zF[3%qZE:T
@MaxMinutes INT, bs<WH`P
@NewSize INT Y{%4F%Oy
USE tablename -- 要操作的数据库名 R=][>\7]}
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 Qh)|FQ[s$r
@MaxMinutes = 10, -- Limit on time allowed to wrap log. g`%ED0aR
@NewSize = 1 -- 你想设定的日志文件的大小(M) Zp/qs
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-- Setup / initialize ^2&O3s
DECLARE @OriginalSize int O!#L#u53
SELECT @OriginalSize = size wQF&GGYR
FROM sysfiles <7vI h0
WHERE name = @LogicalFileName &,m'sQ
SELECT 'Original Size of ' + db_name() + ' LOG is ' + >XD02A[
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + [(D}%+2
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' %f_)<NP9=
FROM sysfiles !~Hafn-1
WHERE name = @LogicalFileName W+#}~2&Dv
CREATE TABLE DummyTrans 4FfwpO3,Ku
(DummyColumn char (8000) not null) ?c|`R1D
DECLARE @Counter INT, U6/m_`nc
@StartTime DATETIME, :0J-ek.;
@TruncLog VARCHAR(255) "'Q" (S
SELECT @StartTime = GETDATE(), kr/1Dsr4
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' {u(}ED#p
DBCC SHRINKFILE (@LogicalFileName, @NewSize) '<RB
EXEC (@TruncLog) V\iIvBpWg
-- Wrap the log if necessary. ,xAM[h&
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired Y(#d8o}}#
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ]>VJ--fH
AND (@OriginalSize * 8 /1024) > @NewSize ~|aeKtCs(.
BEGIN -- Outer loop. WU+Jo@]y
SELECT @Counter = 0 "}]GQt< F
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) EWuiaw.
BEGIN -- update d&[M8(
INSERT DummyTrans VALUES ('Fill Log') *pcbwd!/
DELETE DummyTrans ZaukMEq
SELECT @Counter = @Counter + 1 ?L<UOv7;t
END S7Iu?R_I
EXEC (@TruncLog) C:tSCNH[
END tj"v0u?zW
SELECT 'Final Size of ' + db_name() + ' LOG is ' + H#1*'e>
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + Ux%\Y.PPI
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' !#@4xeBPo
FROM sysfiles 1cHSgpoJ
WHERE name = @LogicalFileName 3/A[LL|
DROP TABLE DummyTrans 6k@% +<1
SET NOCOUNT OFF W(u6J#2
8、说明:更改某个表 ZbZAx:L
exec sp_changeobjectowner 'tablename','dbo' ;y?D1o^r8W
9、存储更改全部表 =0@d|LeZ
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch eB(S+p?
@OldOwner as NVARCHAR(128), @w#gRQCl
@NewOwner as NVARCHAR(128) g|GvJ)VX
AS + e5
DECLARE @Name as NVARCHAR(128) ]AFM Y<mB
DECLARE @Owner as NVARCHAR(128) l ) )~&
DECLARE @OwnerName as NVARCHAR(128) %U=S6<lbj;
DECLARE curObject CURSOR FOR ~n8*@9[
select 'Name' = name, O5G<O(,\
'Owner' = user_name(uid) Up/eV}C
from sysobjects RAD4q"}k
where user_name(uid)=@OldOwner X-G~/n-x
order by name q[y,J
OPEN curObject s0`|G|.}
FETCH NEXT FROM curObject INTO @Name, @Owner !SO$k%b}!
WHILE(@@FETCH_STATUS=0) j &0fC!k
BEGIN 9d,]_l.sB
if @Owner=@OldOwner m>Z\
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begin V(''p{
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ig.6[5a\
exec sp_changeobjectowner @OwnerName, @NewOwner lH,]ZA./
end +AgkPMy
-- select @name,@NewOwner,@OldOwner *Lb(urf
FETCH NEXT FROM curObject INTO @Name, @Owner 0?5%
END V~]'+A
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close curObject n&3iv^
deallocate curObject T
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GO !F7EAQn{(
10、SQL SERVER中直接循环写入数据 9GtVI^]
declare @i int RIVL 0Ig
set @i=1 DiYJlD&
while @i<30 f)AW !/
begin Il&"=LooZ
insert into test (userid) values(@i) 5uD#=/oV
set @i=@i+1 L?D~~Jb
end XTi0,e]5{u
小记存储过程中经常用到的本周,本月,本年函数 `%mBu`A
Dateadd(wk,datediff(wk,0,getdate()),-1) X#Dhk6
Dateadd(wk,datediff(wk,0,getdate()),6) ?,i#B'Z^
Dateadd(mm,datediff(mm,0,getdate()),0) sS1J.R
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) Z68Wf5@to&
Dateadd(yy,datediff(yy,0,getdate()),0) 3"^)bGe
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) `!Ge"JB6
上面的SQL代码只是一个时间段 LDi ezi
Dateadd(wk,datediff(wk,0,getdate()),-1) o+X'(!Trw
Dateadd(wk,datediff(wk,0,getdate()),6) Gwrx)Mq
就是表示本周时间段. +,F=
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下面的SQL的条件部分,就是查询时间段在本周范围内的: ax{-Qi7z-+
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) d_WnK{
而在存储过程中 mtWx ?x
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) |bG [TOa
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) Y;> p)'z