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。 ](9{}DHV
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一、基础 }<\65 B$1
1、说明:创建数据库 n6%jhv9H
CREATE DATABASE database-name M[
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2、说明:删除数据库 hBfzU\*0H
drop database dbname pZ_FVID
3、说明:备份sql server ek{PA!9Sk
--- 创建 备份数据的 device zW"3K
USE master #hE3~+i
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' P2
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--- 开始 备份 z[lRb]:i[
BACKUP DATABASE pubs TO testBack od5w9E.
4、说明:创建新表 P7>C4rmQ
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) -4^@)~Y
根据已有的表创建新表: "mP*}VF
A:create table tab_new like tab_old (使用旧表创建新表) 2p3u6\y
B:create table tab_new as select col1,col2... from tab_old definition only H8t{ >C)]
5、说明:删除新表 L$TKO,T
drop table tabname 1[gjb((
6、说明:增加一个列 C(t6;&H
Alter table tabname add column col type { Sliy'
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。 y8~)/)l&
7、说明:添加主键: Alter table tabname add primary key(col) AXU!-er$
说明:删除主键: Alter table tabname drop primary key(col) -{:LxE
8、说明:创建索引:create [unique] index idxname on tabname(col....) X_s G6Q@
删除索引:drop index idxname 1M~:]}*<
注:索引是不可更改的,想更改必须删除重新建。 | 7'yk__m
9、说明:创建视图:create view viewname as select statement F{H0
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删除视图:drop view viewname <j8&u/Za~'
10、说明:几个简单的基本的sql语句 }rMpp[
选择:select * from table1 where 范围 2W:?#h3
插入:insert into table1(field1,field2) values(value1,value2) u&d v[
删除:delete from table1 where 范围 %}]4Nsd e
更新:update table1 set field1=value1 where 范围 /DG`Hg
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! Uo[5V|>X6
排序:select * from table1 order by field1,field2 [desc] nhXp_Z9
总数:select count as totalcount from table1 7E75s)KH
求和:select sum(field1) as sumvalue from table1 "MS`d+rf\
平均:select avg(field1) as avgvalue from table1 iQ}sp64
最大:select max(field1) as maxvalue from table1 #&2N,M!Q
最小:select min(field1) as minvalue from table1 ~
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11、说明:几个高级查询运算词 ]Y:
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A: UNION 运算符 s)DNLx
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。 gZ >orZL'
B: EXCEPT 运算符 -^xKG'uth
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。 xE-`Bb
C: INTERSECT 运算符 &{4Mo,x
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。 A&lgiR*ObT
注:使用运算词的几个查询结果行必须是一致的。 1>@|
12、说明:使用外连接 ]-Y]Q%A4
A、left outer join: E0B2>V
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。 |&RX>UW$W
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c Qbt>}?-
B:right outer join: 6M vRR
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 NG W{Z~l
C:full outer join: A8Z?[,Mq!
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 +xdFkc
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二、提升 ?gMrcc/{
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) <9.7 gwzE
法一:select * into b from a where 1<>1 oS|~\,p"
法二:select top 0 * into b from a )qP{X,Uf
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) ,~?A.
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insert into b(a, b, c) select d,e,f from b; Ihq@|s8
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) nMdN$E
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 nV xMo_
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. FITaL@{c
4、说明:子查询(表名1:a 表名2:b) n zrCOMld
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) Csm!\I
5、说明:显示文章、提交人和最后回复时间 z,x"vK(
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b xI\s9_"Qy
6、说明:外连接查询(表名1:a 表名2:b) Rpd/9x.)&
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ;)pV[3[
7、说明:在线视图查询(表名1:a ) +rpd0s49
select * from (SELECT a,b,c FROM a) T where t.a > 1; _@;3$eB
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 z2q5f:d8
select * from table1 where time between time1 and time2 3$y L+%i
select a,b,c, from table1 where a not between 数值1 and 数值2 f4y;K>u7p
9、说明:in 的使用方法 T9<nD"=:
select * from table1 where a [not] in ('值1','值2','值4','值6') Fsj&/:
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10、说明:两张关联表,删除主表中已经在副表中没有的信息 ]`H.qV
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) ~#km0<r?
11、说明:四表联查问题: u#,'ys
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 ..... 5Zm_^IS
12、说明:日程安排提前五分钟提醒 ~@?-|xLqQ
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 [ .uaO
13、说明:一条sql 语句搞定数据库分页 GE+csnA2
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 ugPI1'f
14、说明:前10条记录 <$2zr4
select top 10 * form table1 where 范围 F1*rUsRKN
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) ]hVXFHrR
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) CF92AY
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 UKQ&TV}0
(select a from tableA ) except (select a from tableB) except (select a from tableC) ?q }wl\"8
17、说明:随机取出10条数据 =/!S
select top 10 * from tablename order by newid() i*w-Q=
18、说明:随机选择记录 ?,DbV|3_\
select newid() ZDJWd=E
19、说明:删除重复记录 J}KktD@!O
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) "UnSZ[;t
20、说明:列出数据库里所有的表名 QF "&~
select name from sysobjects where type='U' B^Mtj5Oc
21、说明:列出表里的所有的 LK/V]YG
select name from syscolumns where id=object_id('TableName') 0$ac1;7
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。 rh&Eu qE%
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 ByvqwJY
显示结果: ,O{ 5
type vender pcs A0u:Fm{E
电脑 A 1 U(LR('-h
电脑 A 1 <X&:tZ#/
光盘 B 2 K05Y;URbd
光盘 A 2 7]zZha4X
手机 B 3 E'6P>6l5
手机 C 3 $%8n,FJ[
23、说明:初始化表table1 i3j jPN!
TRUNCATE TABLE table1 &YKzK)@
24、说明:选择从10到15的记录 q\Kdu5x{
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc (kOv
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三、技巧 K):sq{
1、1=1,1=2的使用,在SQL语句组合时用的较多 3h4"Rv=,
"where 1=1" 是表示选择全部 "where 1=2"全部不选, }"H900WE|
如: 9GaER+d|
if @strWhere !='' /loNOutw
begin Y
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere --)[>6)I
end @sO.g_yM
else lf#six
begin E|3aiC,5
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' kcUt!PL
end =ab}.dWC
我们可以直接写成 7}.(EZ0
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere *.l=>#qF
2、收缩数据库 h(sKGCG
--重建索引 )\G#[Pc7
DBCC REINDEX IxR:a(
DBCC INDEXDEFRAG ['1?'*
--收缩数据和日志 q)zvePO#
DBCC SHRINKDB {v(|_j&:o
DBCC SHRINKFILE DR8dJ#
3、压缩数据库 p?nVPTh
dbcc shrinkdatabase(dbname) 6d8
4、转移数据库给新用户以已存在用户权限 1+iiiVbMH
exec sp_change_users_login 'update_one','newname','oldname'
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go -E"o)1Pj6C
5、检查备份集 ~VF,qspO
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' *A`^ C
6、修复数据库 DLZ63'
ALTER DATABASE [dvbbs] SET SINGLE_USER 2&#iHv
GO +P.Ir
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK !>j-j
GO c2"OpI
ALTER DATABASE [dvbbs] SET MULTI_USER pUx@ QyrI
GO +.St"f/1
7、日志清除 ppA8c6
SET NOCOUNT ON VF.S)='>Eu
DECLARE @LogicalFileName sysname, S)?B
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@MaxMinutes INT, T^t`Hp
@NewSize INT #D8)rs.9
USE tablename -- 要操作的数据库名 Uz_{jAhW]
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 qm@hD>W+
@MaxMinutes = 10, -- Limit on time allowed to wrap log. []NAV
@NewSize = 1 -- 你想设定的日志文件的大小(M) **"sru;@=
-- Setup / initialize j^M@0o
DECLARE @OriginalSize int UQy+&;#5
SELECT @OriginalSize = size de[_T%A
FROM sysfiles S7R^%Wck/6
WHERE name = @LogicalFileName O^GTPYW
SELECT 'Original Size of ' + db_name() + ' LOG is ' + RIlPH~
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + U*t`hn-xs
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' GS@ wG
FROM sysfiles "]%
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WHERE name = @LogicalFileName #'T@mA
CREATE TABLE DummyTrans h 9/68Gc?6
(DummyColumn char (8000) not null) E#OKeMK
DECLARE @Counter INT, %* 8QLI
@StartTime DATETIME, ):\L#>:w
@TruncLog VARCHAR(255) eZHi6v)i
SELECT @StartTime = GETDATE(), LT!4pD:a
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' va)\uXW.N
DBCC SHRINKFILE (@LogicalFileName, @NewSize) Z|.. hZG
EXEC (@TruncLog) #cA}B
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-- Wrap the log if necessary. 4CqZvdC
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired WA+v&*]
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) LQ._?35r
AND (@OriginalSize * 8 /1024) > @NewSize -95`.o
BEGIN -- Outer loop. ax$0J|}7
SELECT @Counter = 0 yl*S|= 8;k
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) uAJC Q)@
BEGIN -- update 3j2}n
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INSERT DummyTrans VALUES ('Fill Log') ;tj_vmZ@R
DELETE DummyTrans HV>W f"1
SELECT @Counter = @Counter + 1 k0,~wn\#h
END ?mMd6U&J
EXEC (@TruncLog) )pJzw-m"
END )g-*fSa
SELECT 'Final Size of ' + db_name() + ' LOG is ' + WZZD
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + ][9M_.
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' Yq.Omr!
FROM sysfiles r$+9grm<
WHERE name = @LogicalFileName IV\@GM:ait
DROP TABLE DummyTrans mu(S9
SET NOCOUNT OFF "C>KKs }
8、说明:更改某个表 'tOo0Zgc
exec sp_changeobjectowner 'tablename','dbo' _A(J^;?
9、存储更改全部表 TJCoID7a8
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch B^oXUEOImq
@OldOwner as NVARCHAR(128), 6(wpf^br2
@NewOwner as NVARCHAR(128) 5dhRuc
AS \aG>(Mr
DECLARE @Name as NVARCHAR(128) Fw=-gb_.
DECLARE @Owner as NVARCHAR(128) &9'6hMu
DECLARE @OwnerName as NVARCHAR(128) upWq=_
DECLARE curObject CURSOR FOR z\v\T|C
select 'Name' = name, ~;{)S}U@R
'Owner' = user_name(uid) yfq"atj
from sysobjects
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where user_name(uid)=@OldOwner M6?* \9E
order by name D:%v((Ccw
OPEN curObject iNha<iS+
FETCH NEXT FROM curObject INTO @Name, @Owner |n0 )s% 8`
WHILE(@@FETCH_STATUS=0) Pb!kl #
BEGIN )wAqaG_d
if @Owner=@OldOwner o-R;EbL
begin ,Xao{o(
set @OwnerName = @OldOwner + '.' + rtrim(@Name) )t=Cj?5
exec sp_changeobjectowner @OwnerName, @NewOwner ^>[Z~G($
end ^oj)#(3C
-- select @name,@NewOwner,@OldOwner m"`&FA
FETCH NEXT FROM curObject INTO @Name, @Owner 55fV\3F|R
END 2rne=L
close curObject ;/$zBr`'
deallocate curObject 'AHI;Z~Gk
GO \9!W^i[+
10、SQL SERVER中直接循环写入数据 Q[S""P.Z|
declare @i int \DpXs[1
set @i=1 UT+B*?,h
while @i<30 {3'z}q
begin cs,%Zk.xjw
insert into test (userid) values(@i) G!@tW`HO
set @i=@i+1 ]V?\Qv/.=
end y$7<ZBG
小记存储过程中经常用到的本周,本月,本年函数 yX?& K}JI
Dateadd(wk,datediff(wk,0,getdate()),-1) Em-88=XO
Dateadd(wk,datediff(wk,0,getdate()),6) 5nQ*%u\$Z
Dateadd(mm,datediff(mm,0,getdate()),0) hQvSh\p
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 7$k[cL1
Dateadd(yy,datediff(yy,0,getdate()),0) t(}\D]mj
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) fHdPav f,S
上面的SQL代码只是一个时间段 j!xt&t4D
Dateadd(wk,datediff(wk,0,getdate()),-1) #toKT_
Dateadd(wk,datediff(wk,0,getdate()),6) t L}i%7
就是表示本周时间段. LS*^TA(I[
下面的SQL的条件部分,就是查询时间段在本周范围内的: 1@im+R?a
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ](vOH#E
而在存储过程中 P'xq+Q
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) XzIhFX6
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) I#tn/\n