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。 g!DJW
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一、基础 sA!$}W
1、说明:创建数据库 ]YWz;Z
CREATE DATABASE database-name $bsD'Io
2、说明:删除数据库 yU'<b.]
drop database dbname ,v$Q:n|
3、说明:备份sql server :.aMhyh#*
--- 创建 备份数据的 device 2v?fbrC5c
USE master JK'FJ}Z4
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' cogIkB&Ju
--- 开始 备份 ZGj ^,? a
BACKUP DATABASE pubs TO testBack Zi=/w
4、说明:创建新表 ce:p*
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) @jY=b<
根据已有的表创建新表: h'ik19
A:create table tab_new like tab_old (使用旧表创建新表) v8f1o$R
B:create table tab_new as select col1,col2... from tab_old definition only _=-B%m
5、说明:删除新表 Cd2A&RB
drop table tabname -+{<a!Nb
6、说明:增加一个列 U'k 0;
Alter table tabname add column col type fs\A(]`$
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。 M`)/^S9
7、说明:添加主键: Alter table tabname add primary key(col) a]nK!;>$
说明:删除主键: Alter table tabname drop primary key(col) ?/|KM8
8、说明:创建索引:create [unique] index idxname on tabname(col....) '8w>=9Xl
删除索引:drop index idxname AX;!-|bW
注:索引是不可更改的,想更改必须删除重新建。 yc+pNC)ue_
9、说明:创建视图:create view viewname as select statement :T )R;E@
删除视图:drop view viewname N> xdX5
10、说明:几个简单的基本的sql语句 a(uZ}yS$
选择:select * from table1 where 范围 5yk#(i7C
插入:insert into table1(field1,field2) values(value1,value2) zd|n!3;
删除:delete from table1 where 范围 5y8VA4L/o
更新:update table1 set field1=value1 where 范围 c*.-mS~Z`
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! @L$!hTaP
排序:select * from table1 order by field1,field2 [desc] dVe,;?+A
总数:select count as totalcount from table1 Q>(a JF
求和:select sum(field1) as sumvalue from table1 QtQbr*q@%
平均:select avg(field1) as avgvalue from table1 =}zSj64
最大:select max(field1) as maxvalue from table1 OXJ'-EZH
最小:select min(field1) as minvalue from table1 * o{7 a$V
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11、说明:几个高级查询运算词 _Wqy,L;J
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A: UNION 运算符 OE*Y%*b
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。 '^)}"sZ@G
B: EXCEPT 运算符 lhC hk7l
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。 `I.pwst8i-
C: INTERSECT 运算符 Q_>W!)p Gz
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。 g%<n9AUl
注:使用运算词的几个查询结果行必须是一致的。 !_P&SmK3
12、说明:使用外连接 u4j"U6"]M
A、left outer join: ?N^1v&Q
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。 +z4E:v
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 F3hG8YX
B:right outer join: *3)kr=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。 LcZ|A;it
C:full outer join: J$5Vjh'aM
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。 .,20_<j%=
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二、提升 +Qf}&D_
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) tzthc*-<
法一:select * into b from a where 1<>1 inip/&P?V
法二:select top 0 * into b from a .cbC2t95
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 2vWn(6`
insert into b(a, b, c) select d,e,f from b; tva=DS
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) yzv"sd[8N
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 yM~bUmSg
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. $1g1Bn
4、说明:子查询(表名1:a 表名2:b) LT"H-fTgs
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) *MB>,HU
5、说明:显示文章、提交人和最后回复时间 -Caj>K
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b hGkJ$QT
6、说明:外连接查询(表名1:a 表名2:b) 5VJe6i9;
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c Ulx]4;uzf
7、说明:在线视图查询(表名1:a ) g/fpXO\
select * from (SELECT a,b,c FROM a) T where t.a > 1; 1[T7;i$
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 H>A6VDu
select * from table1 where time between time1 and time2 IzJq:G.
select a,b,c, from table1 where a not between 数值1 and 数值2 B0%=! &
9、说明:in 的使用方法 9h?'zyX
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select * from table1 where a [not] in ('值1','值2','值4','值6') g4eW<
10、说明:两张关联表,删除主表中已经在副表中没有的信息 a]T&-#c,}
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) BjeD4
11、说明:四表联查问题: 0~z\WSo
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 ..... 1"L"LU'
12、说明:日程安排提前五分钟提醒 !~yBzH;K
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 bi^?SH\
13、说明:一条sql 语句搞定数据库分页 E^zfI9R
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 oFf9KHorW
14、说明:前10条记录 T4HJy|
select top 10 * form table1 where 范围 t:5-Ro
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.) #,u|*O:
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) z V\+za,
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 t2s/zxt
(select a from tableA ) except (select a from tableB) except (select a from tableC) 10i$ b<O
17、说明:随机取出10条数据 o$buoGSPc
select top 10 * from tablename order by newid() 0'fswa)
18、说明:随机选择记录 XS">`9o!
select newid() kJp~'\b
19、说明:删除重复记录 tw>2<zmSi%
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) zD79 M
20、说明:列出数据库里所有的表名 p*&0d@'r
select name from sysobjects where type='U' ?UZt30|1
21、说明:列出表里的所有的 Z sTtSM\Ac
select name from syscolumns where id=object_id('TableName')
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22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 z8'1R6nq
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type M{Z
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显示结果: m$kQbPlatN
type vender pcs lOk8VlH<h
电脑 A 1 9MYk5q.X:
电脑 A 1 pX
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光盘 B 2 QCF'/G
光盘 A 2 ^w.hI5ua)
手机 B 3 &J*M
手机 C 3 C=/B\G/.9
23、说明:初始化表table1 {^
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TRUNCATE TABLE table1 ^Aq0<
24、说明:选择从10到15的记录 jk{(o09
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc b1.*cIv}
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三、技巧 ~vF a\7sf
1、1=1,1=2的使用,在SQL语句组合时用的较多 LmePJ
"where 1=1" 是表示选择全部 "where 1=2"全部不选, |zYOCDFf
如: {O^u^a\m
if @strWhere !='' C/Khp +
begin {P]C>
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere l9I r@.m
end D j&~x
else iqQT ^
begin t?W}=%M[
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' X#lNS+&='
end $(aq;DR
我们可以直接写成 :TH cI;PG8
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere "6$V1B0KW
2、收缩数据库 @1JwjtNk
--重建索引 _\}'5nmw\
DBCC REINDEX wZiUzS;v
DBCC INDEXDEFRAG -{cHp
--收缩数据和日志 PgWWa*Ew
DBCC SHRINKDB lW&(dn)}
DBCC SHRINKFILE xH-d<Ht,7
3、压缩数据库 ,^UqE{
dbcc shrinkdatabase(dbname) Cbw *?9d
4、转移数据库给新用户以已存在用户权限 n|w+08c"
exec sp_change_users_login 'update_one','newname','oldname' )/H;5 cn
go Km`
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5、检查备份集 0
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RESTORE VERIFYONLY from disk='E:\dvbbs.bak' XA>W>|
6、修复数据库 :v&[!
ALTER DATABASE [dvbbs] SET SINGLE_USER $MQ}+*Wr
GO >lQo _p(;
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK Zv u6/#
GO ze+YQF
ALTER DATABASE [dvbbs] SET MULTI_USER zUfq.
GO xM*_1+<dT$
7、日志清除 "O&93#8
SET NOCOUNT ON Q`ua9oIJ=
DECLARE @LogicalFileName sysname, ^SdF\uk{?6
@MaxMinutes INT, T*z]<0E]
@NewSize INT Xwm3# o.&)
USE tablename -- 要操作的数据库名 l!mbpFt
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 Z'z)Oo
@MaxMinutes = 10, -- Limit on time allowed to wrap log. rbw$=bX}
@NewSize = 1 -- 你想设定的日志文件的大小(M) )g0lI
-- Setup / initialize h0GoF A<
DECLARE @OriginalSize int k ut=(;
SELECT @OriginalSize = size ZZw`8 E
FROM sysfiles -Zt!H%U
WHERE name = @LogicalFileName RZOK+!H:
SELECT 'Original Size of ' + db_name() + ' LOG is ' + WRh5v8Wz0
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + Jh26!%<Bl
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' Q]:O#;"<
FROM sysfiles g{8RPw]
WHERE name = @LogicalFileName #2{-6ey
CREATE TABLE DummyTrans f98,2I(>`+
(DummyColumn char (8000) not null) |3*9+4]a
DECLARE @Counter INT, jjs/6sSRk
@StartTime DATETIME, sVLvnX,
@TruncLog VARCHAR(255) 9BCW2@Kp
SELECT @StartTime = GETDATE(), :RaQ
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@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' C"{^wy{sL
DBCC SHRINKFILE (@LogicalFileName, @NewSize) aAo|3KCs
EXEC (@TruncLog) "HMEoZ
-- Wrap the log if necessary. {keZ_2
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 1|bXIY.J*
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) +#}GmUwPG$
AND (@OriginalSize * 8 /1024) > @NewSize eA/n.V$z
BEGIN -- Outer loop. $@g]?*L:
SELECT @Counter = 0 ~6[?=mOi'
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) p@<Q?
BEGIN -- update &OMlW_FHR
INSERT DummyTrans VALUES ('Fill Log') V>@[\N[
DELETE DummyTrans U&!TA(Yr
SELECT @Counter = @Counter + 1 YB#fAU
END =$>=EBH,cm
EXEC (@TruncLog) `+7F H
END kB7vc>@1
SELECT 'Final Size of ' + db_name() + ' LOG is ' + !NXjax\r
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + $%<{zWQm
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ?|nl93m
FROM sysfiles 7#V7D6j1
WHERE name = @LogicalFileName MqyjTY::Xg
DROP TABLE DummyTrans %pC<T*f
SET NOCOUNT OFF *}?[tR5
8、说明:更改某个表 j6
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exec sp_changeobjectowner 'tablename','dbo' X\}l" ]
9、存储更改全部表 R+ * ; [
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch pwFp<O"
@OldOwner as NVARCHAR(128), ewDYu=`*
@NewOwner as NVARCHAR(128) -^_m(@A<~
AS "F
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DECLARE @Name as NVARCHAR(128) _jWs(OmJ
DECLARE @Owner as NVARCHAR(128) YagfCi ?
DECLARE @OwnerName as NVARCHAR(128) YEL0h0gn
DECLARE curObject CURSOR FOR 7CIN!vrC|1
select 'Name' = name, 5cSiV7#Y:
'Owner' = user_name(uid) -<W?it?D
from sysobjects ]\E"oZ
where user_name(uid)=@OldOwner Q@D7\<t
order by name 5mH[|_
OPEN curObject !3Q0Ahf
FETCH NEXT FROM curObject INTO @Name, @Owner q+g,?;Yx
WHILE(@@FETCH_STATUS=0) _&gi4)q
BEGIN |/Nh#
if @Owner=@OldOwner |'^s3i&w
begin E^F"$Z"N
set @OwnerName = @OldOwner + '.' + rtrim(@Name) OO:S2-]Y>e
exec sp_changeobjectowner @OwnerName, @NewOwner X! d-"[
end mdi!Q1pS
-- select @name,@NewOwner,@OldOwner r\NqY.U&
FETCH NEXT FROM curObject INTO @Name, @Owner qu=~\t1[6
END ,Qj G|P
close curObject m`yvZ4K!
deallocate curObject "1O_h6C
GO i3-5~@M
10、SQL SERVER中直接循环写入数据 b<h((]Q>^
declare @i int v%tjZ5x
set @i=1
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while @i<30 $BqiC!~
begin 0.MB;gm:
insert into test (userid) values(@i) AHf 9H?
set @i=@i+1 Vt`4u5HG
end #S>N}<>
小记存储过程中经常用到的本周,本月,本年函数 dOjly,!
Dateadd(wk,datediff(wk,0,getdate()),-1) (zhZ}C,VF
Dateadd(wk,datediff(wk,0,getdate()),6) 2&6D`{"P
Dateadd(mm,datediff(mm,0,getdate()),0) HQ-[k$d
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Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 7@ym:6Y+]
Dateadd(yy,datediff(yy,0,getdate()),0) "4b{YWv
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) rZK h}E
上面的SQL代码只是一个时间段 -l[H]BAMXy
Dateadd(wk,datediff(wk,0,getdate()),-1) K,4Ig!
Dateadd(wk,datediff(wk,0,getdate()),6) z#{Y>.b
就是表示本周时间段. FZ*"^=)`G
下面的SQL的条件部分,就是查询时间段在本周范围内的: " ityx?
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) l\_!oa~
而在存储过程中 ?1Nz
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select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) kQ\GVI11?
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) ]TvMT