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。 ]P$DAi
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一、基础 t`,IW{
1、说明:创建数据库 ZD%_PgiT
CREATE DATABASE database-name YnWl'{[ C
2、说明:删除数据库 <WJ0St
drop database dbname gj,J3x4TK/
3、说明:备份sql server y
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--- 创建 备份数据的 device ue"?S6
USE master t1{}-JlA
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' v|(b,J3
--- 开始 备份 O + &
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BACKUP DATABASE pubs TO testBack !(K{*7|h
4、说明:创建新表 b6vYM_ Q
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) -0da"AB
根据已有的表创建新表: oB
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A:create table tab_new like tab_old (使用旧表创建新表) .p(l+
B:create table tab_new as select col1,col2... from tab_old definition only \_AEuz3
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5、说明:删除新表 &AcFa<U
drop table tabname #L:P
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6、说明:增加一个列 "q^'5p]
Alter table tabname add column col type &vX!7Y
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 [=6~"!P}
7、说明:添加主键: Alter table tabname add primary key(col) q)ql]iH
说明:删除主键: Alter table tabname drop primary key(col) MW~B[%/
8、说明:创建索引:create [unique] index idxname on tabname(col....) 9[{>JRm.
删除索引:drop index idxname `L#?eQ{
注:索引是不可更改的,想更改必须删除重新建。 2^#UO=ct
9、说明:创建视图:create view viewname as select statement ;sR6dT)
删除视图:drop view viewname ?_>^<1I1
10、说明:几个简单的基本的sql语句 G=HxD4l
选择:select * from table1 where 范围 NJf(,Mr*|
插入:insert into table1(field1,field2) values(value1,value2) ]}7rWs[|1
删除:delete from table1 where 范围 pEj^x[b`^
更新:update table1 set field1=value1 where 范围 pptM&Y
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! MlK`sH6
排序:select * from table1 order by field1,field2 [desc] zWs*kTtA
总数:select count as totalcount from table1 qf`xH"$
求和:select sum(field1) as sumvalue from table1 ` u\z!x'
平均:select avg(field1) as avgvalue from table1 9m!! b{
最大:select max(field1) as maxvalue from table1 QlYs7zZ
最小:select min(field1) as minvalue from table1 SWjQ.aM
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11、说明:几个高级查询运算词 _*ouo<x
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A: UNION 运算符 uy _i{Y|
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^>S?L-
B: EXCEPT 运算符 Ogke*qM
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\eBfW,/
C: INTERSECT 运算符 RC{Z)M{~
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。 aXbNDj
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注:使用运算词的几个查询结果行必须是一致的。 n_aNs]C9R
12、说明:使用外连接 W0MnGzZ
A、left outer join: 04guud }
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。 EKeh>3;?
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 `X<`j6zaG
B:right outer join: [s{r$!Gl
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 Y3$PQwn
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C:full outer join: 25a#eDbqi
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。 PIEW \i
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二、提升 |\%F(d330
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) 3> \fP#oQ
法一:select * into b from a where 1<>1 C8qTz".5$
法二:select top 0 * into b from a hK39_A-
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ;eW'}&|LV
insert into b(a, b, c) select d,e,f from b; r*N~. tFo
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) i=1 }lkq
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 K@jSr*\'
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. w,![;wG
4、说明:子查询(表名1:a 表名2:b) }WO9!E(
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) ;4kx >x*H
5、说明:显示文章、提交人和最后回复时间 te;Ox!B&
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b @0ov!9]Rw-
6、说明:外连接查询(表名1:a 表名2:b) &cu] vw
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c *hZ~i{c,7
7、说明:在线视图查询(表名1:a ) N$%61GiulT
select * from (SELECT a,b,c FROM a) T where t.a > 1; >{ECyh;
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 &7($kj
select * from table1 where time between time1 and time2 r2SJp@f
select a,b,c, from table1 where a not between 数值1 and 数值2 uGa(_ut
9、说明:in 的使用方法 'l'
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select * from table1 where a [not] in ('值1','值2','值4','值6') 0n*rs=\VG
10、说明:两张关联表,删除主表中已经在副表中没有的信息 VZ2.w4b
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Bzu(XQ
11、说明:四表联查问题: /1 US,
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 ..... pymx\Hd,
12、说明:日程安排提前五分钟提醒 $!F&>=o
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 7}d$*C
13、说明:一条sql 语句搞定数据库分页 E#<7\p>
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 EvqUNnjR
14、说明:前10条记录 i'!jx.
select top 10 * form table1 where 范围 cB ab2/
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.) 8lOZIbwS
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ..jq[(;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 #u8*CA9
(select a from tableA ) except (select a from tableB) except (select a from tableC) VR4E
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17、说明:随机取出10条数据 :'d76pM-
select top 10 * from tablename order by newid() :/@k5#DY
18、说明:随机选择记录 (|<h^]
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select newid() |7QVMFZ
19、说明:删除重复记录 E 4='m
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) p*pn@z
20、说明:列出数据库里所有的表名 Iys6R?~
select name from sysobjects where type='U' HZDk
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21、说明:列出表里的所有的 { r6]MS#l1
select name from syscolumns where id=object_id('TableName') O1?B{F/ e
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 [fo'M
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 ^91sl5c8yD
显示结果: "u(S2'DW'(
type vender pcs wTTTrk
电脑 A 1 iN<(O7B;
电脑 A 1 G-\<5]k]
光盘 B 2 [i(Cl}
光盘 A 2 DC|xilP1O
手机 B 3 9 m\)\/V
手机 C 3 S9G8aea/
23、说明:初始化表table1 tLS<0
TRUNCATE TABLE table1 K08 iPIkQ
24、说明:选择从10到15的记录 Cq?',QU6j
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc _YH<YOrMh
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三、技巧 *>e~_{F
1、1=1,1=2的使用,在SQL语句组合时用的较多 |x d@M-ln
"where 1=1" 是表示选择全部 "where 1=2"全部不选, j:HH#U
如: A$7Eo`Of
if @strWhere !='' ElQJ\%
begin uQ:Qb|
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere 6oj4Rg+(
end DUZQO{V
else !Z
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begin "?i>p z
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' 5U0ytDZ2/(
end '"`
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我们可以直接写成 968Ac}OA
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 4)c+t"h
2、收缩数据库 IIq"e~"Vs
--重建索引 ')C|`(hs
DBCC REINDEX ,3:QB_
DBCC INDEXDEFRAG 4-y6MH
--收缩数据和日志 RI(=HzB
DBCC SHRINKDB 7'_nc!ME
DBCC SHRINKFILE Sdgb#?MR|
3、压缩数据库 %S{o5txo
dbcc shrinkdatabase(dbname) nHSTeFI?
4、转移数据库给新用户以已存在用户权限 uDILjOT
exec sp_change_users_login 'update_one','newname','oldname' T|;^.TZ
go McEmd.S<n
5、检查备份集 }l.KpdRT2
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' LkaG8#m1R
6、修复数据库 M$,Jg5Dc
ALTER DATABASE [dvbbs] SET SINGLE_USER mYjf5
GO dKU5;
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK cICHRp&&
GO M|U';2hZN:
ALTER DATABASE [dvbbs] SET MULTI_USER Lb!r(o>8Cb
GO (tJ91SBl
7、日志清除 LL{t5(- _
SET NOCOUNT ON Ip>^O/}$1
DECLARE @LogicalFileName sysname, +d =~LQ}*
@MaxMinutes INT, q1UBKhpnH
@NewSize INT 'yE*|Sx
USE tablename -- 要操作的数据库名 e:qo_eSC^-
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 u-lrTa""z
@MaxMinutes = 10, -- Limit on time allowed to wrap log. SLSF
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@NewSize = 1 -- 你想设定的日志文件的大小(M) !0b%Jh
-- Setup / initialize *0O<bm
DECLARE @OriginalSize int iNt 4>
SELECT @OriginalSize = size FnY$)o;
FROM sysfiles ]+AAT=B<!
WHERE name = @LogicalFileName MM7"a?y)
SELECT 'Original Size of ' + db_name() + ' LOG is ' + \ZqK\=
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 8AryIgy>@
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' r9?o$=T
FROM sysfiles n9DbiL1{
WHERE name = @LogicalFileName fc3 Fi'^
CREATE TABLE DummyTrans A xf^hBP
(DummyColumn char (8000) not null) oK)[p!D?0{
DECLARE @Counter INT, C]/&vh7ta
@StartTime DATETIME, Hv3W{|
@TruncLog VARCHAR(255) &T7cH>E'K^
SELECT @StartTime = GETDATE(), I:nI6gF
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' uw_H:-J
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 691G15
EXEC (@TruncLog) ^L ]B5,}-
-- Wrap the log if necessary. +Jdm#n?_
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired _1P`]+K\D$
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) U3/8A:$y
AND (@OriginalSize * 8 /1024) > @NewSize qT$)Rb&
BEGIN -- Outer loop. B.}cB'|
SELECT @Counter = 0 V#NtBreN
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ~ibF M5m
BEGIN -- update RYH)AS4w'
INSERT DummyTrans VALUES ('Fill Log') `&H04x"Y$>
DELETE DummyTrans !f`5B( @
SELECT @Counter = @Counter + 1 >{b3>s~T
END ac|/Y$\w
EXEC (@TruncLog) .ots?Ns
END N2T&,&,t
SELECT 'Final Size of ' + db_name() + ' LOG is ' + &5d\~{;
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + 8]HY. $E
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' -n-Z/5~ X
FROM sysfiles 6(>WGR
WHERE name = @LogicalFileName =D5wqCT(Q
DROP TABLE DummyTrans Ts#pUoE~+H
SET NOCOUNT OFF Gp8psH
8、说明:更改某个表 wh*:\_!0\
exec sp_changeobjectowner 'tablename','dbo' ^;4YZwW5w
9、存储更改全部表
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CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch xvB8YW"
@OldOwner as NVARCHAR(128), lA]N04 d
@NewOwner as NVARCHAR(128) AJdp6@O+
AS bLco:-G1E1
DECLARE @Name as NVARCHAR(128) L ?Cjo4xS
DECLARE @Owner as NVARCHAR(128) n7S;
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DECLARE @OwnerName as NVARCHAR(128) =gs~\q
DECLARE curObject CURSOR FOR pr/'J!{^
select 'Name' = name, (7~%B"
'Owner' = user_name(uid) >4M<W4
from sysobjects ,WGc7NN`
where user_name(uid)=@OldOwner S2Vx e@b)
order by name 14-]esSa
OPEN curObject %i595Ij-]
FETCH NEXT FROM curObject INTO @Name, @Owner p(?g-
WHILE(@@FETCH_STATUS=0) ($'V&x8T
BEGIN w,/6B&|
if @Owner=@OldOwner E<k^S{
begin zIm-X,~I$
set @OwnerName = @OldOwner + '.' + rtrim(@Name) 5VZjDg?
exec sp_changeobjectowner @OwnerName, @NewOwner ]VDn'@uM
end Bq;1^gtpe
-- select @name,@NewOwner,@OldOwner MnS+ nH!d
FETCH NEXT FROM curObject INTO @Name, @Owner
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END lC4PKmno
close curObject kP?_kMOx
deallocate curObject {Xv3:"E"O
GO ]=Pu\eE
10、SQL SERVER中直接循环写入数据 ]'g:B p
declare @i int @k9Pz<ub
set @i=1 7f
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while @i<30 0MrN:M2B
begin ^vM_kArA
insert into test (userid) values(@i) 1]Lh'.1^
set @i=@i+1 P7UJ-2%Y+
end R>HY:-2
小记存储过程中经常用到的本周,本月,本年函数 }1@E"6kF
Dateadd(wk,datediff(wk,0,getdate()),-1) ^cn@?k((A
Dateadd(wk,datediff(wk,0,getdate()),6) #a'r_K=ch)
Dateadd(mm,datediff(mm,0,getdate()),0) sG1BNb_
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ST%
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Dateadd(yy,datediff(yy,0,getdate()),0) wASX\D }
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) SBL+e]P
上面的SQL代码只是一个时间段 ?Sw /(}|m
Dateadd(wk,datediff(wk,0,getdate()),-1) !-,Ww[G>
Dateadd(wk,datediff(wk,0,getdate()),6) +A\V )
就是表示本周时间段. q :8\e
下面的SQL的条件部分,就是查询时间段在本周范围内的: K_&_z
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) vpV$$=Qwp
而在存储过程中 R[Nbtbv9Q
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) 5*1#jiq
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 61>f(?s