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。 5fDVJE "9"
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一、基础 +*mi%)I
1、说明:创建数据库 z3[
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CREATE DATABASE database-name |ILj}4ZA7
2、说明:删除数据库 $wub)^
drop database dbname yiWBIJ2Wu9
3、说明:备份sql server r`HtN{6r
--- 创建 备份数据的 device ezgP\ct
USE master {D 9m//x
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' G;>b}\Ng
--- 开始 备份 9jCn|+
BACKUP DATABASE pubs TO testBack ^fQ ]>/u
4、说明:创建新表 *[9FPya
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) z ~#
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根据已有的表创建新表: _2R;@[f2
A:create table tab_new like tab_old (使用旧表创建新表) 4'RyD<K\
B:create table tab_new as select col1,col2... from tab_old definition only GNgPf"}K
5、说明:删除新表 |B./5 ,nSS
drop table tabname xf_NHKZ)
6、说明:增加一个列 0 P3^#j
Alter table tabname add column col type iqRk\yq<
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 h2QoBGL5
7、说明:添加主键: Alter table tabname add primary key(col) @6~r7/WD
说明:删除主键: Alter table tabname drop primary key(col) +Vl\lL
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8、说明:创建索引:create [unique] index idxname on tabname(col....) `07xW*K(\Y
删除索引:drop index idxname h;u8{t"
注:索引是不可更改的,想更改必须删除重新建。 |$f.Qs~?
9、说明:创建视图:create view viewname as select statement 9o@5:.b<j
删除视图:drop view viewname /xUTm=w7u
10、说明:几个简单的基本的sql语句 {U=Mfo?AH
选择:select * from table1 where 范围 )! Jo7SR
插入:insert into table1(field1,field2) values(value1,value2) yM`J+tq
删除:delete from table1 where 范围 Y(h86>z*w
更新:update table1 set field1=value1 where 范围 p~J|l$%0rQ
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! Po~{Mpe
排序:select * from table1 order by field1,field2 [desc] ,9SBGxK5`
总数:select count as totalcount from table1 w@ALl#z;}
求和:select sum(field1) as sumvalue from table1 IlJ!jq
平均:select avg(field1) as avgvalue from table1 nYhI0q
最大:select max(field1) as maxvalue from table1 (&H-v'a}3
最小:select min(field1) as minvalue from table1 H$bu*o-Z
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11、说明:几个高级查询运算词 >> yK_yg
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A: UNION 运算符 ]q~_
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。 G6]W'Kk
B: EXCEPT 运算符 pN|BtrN{
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。 =4+Wx8ZeW
C: INTERSECT 运算符 :08b&myx
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。 l|TiUjs
注:使用运算词的几个查询结果行必须是一致的。 6jyS]($q
12、说明:使用外连接 Kx==vq%39
A、left outer join: >c
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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。 qS1byqq78l
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 us%dw&
B:right outer join: 2l^hnog|
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。 XRARgWj
C:full outer join: -9W)|toWb"
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。 .K%1{`.|
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二、提升 xvn@zi
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) *|n-Hr
法一:select * into b from a where 1<>1 !:"$1kh1("
法二:select top 0 * into b from a WD.td
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) 4}-{sS}MP
insert into b(a, b, c) select d,e,f from b; +||y/}1
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) jRdmQmTJ
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 *f<+yF{=A
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. .S4c<pMap
4、说明:子查询(表名1:a 表名2:b) Y=0D[o8
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) .xG3`YH
5、说明:显示文章、提交人和最后回复时间 ~nLE?>x|Z
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b %+gK5aVab
6、说明:外连接查询(表名1:a 表名2:b) ul@G{N{L
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c lqdil l\
7、说明:在线视图查询(表名1:a ) <Cv6wC=
select * from (SELECT a,b,c FROM a) T where t.a > 1; p8gm=
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 g}\G@7Q
select * from table1 where time between time1 and time2 xb8S)zO]Q
select a,b,c, from table1 where a not between 数值1 and 数值2 5AFy6Ab
9、说明:in 的使用方法 ^phgNzD
select * from table1 where a [not] in ('值1','值2','值4','值6') qrdA4S
10、说明:两张关联表,删除主表中已经在副表中没有的信息 [9N>*dKB
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) :]]#X
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11、说明:四表联查问题: #7(?B{i
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 ..... "wqN,}bj\
12、说明:日程安排提前五分钟提醒 Uphme8SX
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 $>if@}u
13、说明:一条sql 语句搞定数据库分页 VDy2!0
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 gs/ i%O
14、说明:前10条记录 e 97Ll=>
select top 10 * form table1 where 范围 ZhvZe/
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) bEvlk\iql
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) R"Ff(1m
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 T- ~l2u|s
(select a from tableA ) except (select a from tableB) except (select a from tableC) Pk{eGG<F$
17、说明:随机取出10条数据 2&b?NqEeZ
select top 10 * from tablename order by newid() )O}q{4,}
18、说明:随机选择记录 $f>h_8cla
select newid() 41^ =z[k
19、说明:删除重复记录 }Zuk}Og9+
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) {~*^jS']5
20、说明:列出数据库里所有的表名 ;zF3e&e(
select name from sysobjects where type='U' VAD9mS^~
21、说明:列出表里的所有的 |!Ryl}Oi
select name from syscolumns where id=object_id('TableName') r3OR7f[
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 vIzREu|5
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type esh7*,7-z*
显示结果: Gn?NY}.S
type vender pcs rm}%C(C{J
电脑 A 1 Fi!BXngbd
电脑 A 1 'GyO
光盘 B 2 PAYS~MnV@3
光盘 A 2 ctk~}(1#
手机 B 3 uT :Yh6
手机 C 3
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23、说明:初始化表table1 ?Sj>b
TRUNCATE TABLE table1 :)*+aS"
24、说明:选择从10到15的记录 8GN_3pT
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc lq'MLg
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三、技巧 u2 a#qU5*
1、1=1,1=2的使用,在SQL语句组合时用的较多 VvFMpPi
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 6<hE]B)
如: 5 *R{N
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if @strWhere !='' 'zo]
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begin MrU0Jrk4+
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere |&49YQ
end :@~W$f\y
else kN~:Bh$
begin ~vPR9\e
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' ' pN[H\Ia
end .91@T.
我们可以直接写成 q}xYme4
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ;n\$'"K&;
2、收缩数据库 ;07>ZH%
--重建索引 tEam6xNf,
DBCC REINDEX ATG;*nIP
DBCC INDEXDEFRAG 93[&'
--收缩数据和日志 '$q=r x
DBCC SHRINKDB =:"wU
DBCC SHRINKFILE gVscdg5
3、压缩数据库 :w,#RcW
dbcc shrinkdatabase(dbname) UFSbu5 j
4、转移数据库给新用户以已存在用户权限 my]t[%Q{
exec sp_change_users_login 'update_one','newname','oldname' WeiDg,]e$b
go ,
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5、检查备份集 E;MelK<8(
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' })F.Tjf*
6、修复数据库 f`W)Z$fN5
ALTER DATABASE [dvbbs] SET SINGLE_USER )Vf!U"
GO =bHS@h8N<
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK Abc%VRsT
GO
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ALTER DATABASE [dvbbs] SET MULTI_USER Q94Lq~?YF
GO x>!bvZ2
7、日志清除 23p1Lb9P
SET NOCOUNT ON S.,5vI"s,
DECLARE @LogicalFileName sysname, DQI
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@MaxMinutes INT, ;R[w}#Sm
@NewSize INT Jk=_8Xvr`
USE tablename -- 要操作的数据库名 ]#sF
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SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 pNnZ-R|u
@MaxMinutes = 10, -- Limit on time allowed to wrap log. A)%!9i)
@NewSize = 1 -- 你想设定的日志文件的大小(M) MBn ZO
-- Setup / initialize GoUsB|-\
DECLARE @OriginalSize int q@=3`yQ
SELECT @OriginalSize = size ^B?brH}
FROM sysfiles n@te.,?A"
WHERE name = @LogicalFileName mMOjV_
SELECT 'Original Size of ' + db_name() + ' LOG is ' + F%ffnEJg
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + xP7#`S6W
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' )R^&u`k
FROM sysfiles nh'TyUd!
WHERE name = @LogicalFileName \=&F\EV
CREATE TABLE DummyTrans L/c`t7
(DummyColumn char (8000) not null) =@ d/SZ|(E
DECLARE @Counter INT, zI.%b7wq
@StartTime DATETIME, 3j7Na#<tL3
@TruncLog VARCHAR(255) S
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SELECT @StartTime = GETDATE(), 7R7e3p,K
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 6>NK2} `
DBCC SHRINKFILE (@LogicalFileName, @NewSize) ){I!orQ
EXEC (@TruncLog) "$#<+H>O
-- Wrap the log if necessary. PpLuN12H
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired 8|) $;.
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) N?s`a;Q[=
AND (@OriginalSize * 8 /1024) > @NewSize Whl^~$+f
BEGIN -- Outer loop. q}|_]R_y
SELECT @Counter = 0 O|AY2QH\
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) =&t]R?
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BEGIN -- update kyH0J[/n
INSERT DummyTrans VALUES ('Fill Log')
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DELETE DummyTrans Am@:<J
SELECT @Counter = @Counter + 1 d+WNg2#v
END [x{Ai(
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EXEC (@TruncLog) M(U<H;Csk
END 4DgH/Yo
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 6an= C_Mb`
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + "t)$4gERK
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' z'&tmje[?
FROM sysfiles U1;&G
WHERE name = @LogicalFileName z7_h$v
DROP TABLE DummyTrans \C<'2KZR,
SET NOCOUNT OFF {|B
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8、说明:更改某个表 S|
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exec sp_changeobjectowner 'tablename','dbo' $d*PY_
9、存储更改全部表 HChlkj'7w0
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch d6e$'w@(\T
@OldOwner as NVARCHAR(128), M2Jb<y]
@NewOwner as NVARCHAR(128) hem>@Bp'V
AS n{I1ZlEeh
DECLARE @Name as NVARCHAR(128) 1t/mq?z:
DECLARE @Owner as NVARCHAR(128) B9dc*
DECLARE @OwnerName as NVARCHAR(128) \GPTGi5A
DECLARE curObject CURSOR FOR l T#WM]
select 'Name' = name, )kEH}P&
'Owner' = user_name(uid) {X10,
from sysobjects ntQW+!s;P
where user_name(uid)=@OldOwner /:@)De(S
order by name 6~OJB!
OPEN curObject kgHZaQnD
FETCH NEXT FROM curObject INTO @Name, @Owner ?kULR0uL+
WHILE(@@FETCH_STATUS=0) W3gHzT?{
BEGIN "&C>=
if @Owner=@OldOwner O>"T*
begin ~"VM_Lz]5
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ue1g(;
exec sp_changeobjectowner @OwnerName, @NewOwner n0QHrIf{
end b!<)x}-t>
-- select @name,@NewOwner,@OldOwner a+^,EY
FETCH NEXT FROM curObject INTO @Name, @Owner 9@8'*a{`m
END WP{U9YF2
close curObject 9aBz%* xo
deallocate curObject w>e+UW25Y
GO NG8F'=<
10、SQL SERVER中直接循环写入数据 L{0\M`B-
declare @i int {>Hn:jW<.
set @i=1 mwutv8?
while @i<30 =I0J1Ob
begin f#McTC3C
insert into test (userid) values(@i) wb>"'%
set @i=@i+1 NJCSo(O
end &2nICAN[
小记存储过程中经常用到的本周,本月,本年函数 @JPz|
Dateadd(wk,datediff(wk,0,getdate()),-1) sI6I5
Dateadd(wk,datediff(wk,0,getdate()),6) 7+;.Q
Dateadd(mm,datediff(mm,0,getdate()),0) M8R/a[ -A
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) "R\D:Olb#
Dateadd(yy,datediff(yy,0,getdate()),0) C;?<WtH
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) \dbaY: (
上面的SQL代码只是一个时间段 d;nk>6<|
Dateadd(wk,datediff(wk,0,getdate()),-1) RI<&cgWn+<
Dateadd(wk,datediff(wk,0,getdate()),6) R*?!xDJ
就是表示本周时间段. ^Y%<$IFG
下面的SQL的条件部分,就是查询时间段在本周范围内的: 6_&S
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Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) "E@A~<RKP
而在存储过程中 z31g"
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) nRyx2\Py+
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) y eam-8