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>)TG
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一、基础 SoXX}<~E4
1、说明:创建数据库 7Ap~7)z[
CREATE DATABASE database-name $v?! 6:
2、说明:删除数据库 )<]w23i
drop database dbname 4z-,M7iP
3、说明:备份sql server clR?< LO
--- 创建 备份数据的 device "c !oOaA
USE master A
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EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' OI]K_ m3
--- 开始 备份 }v'PY/d.
BACKUP DATABASE pubs TO testBack *`S)@'@:(
4、说明:创建新表 k^'d@1z;C
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) }jyS\drJ
根据已有的表创建新表: yp^[]Mz=
A:create table tab_new like tab_old (使用旧表创建新表) =Nv=Q mO
B:create table tab_new as select col1,col2... from tab_old definition only ga2Q3mV
5、说明:删除新表 Z)6nu)
drop table tabname j-C42Pfr
6、说明:增加一个列 W O+?gu
Alter table tabname add column col type 0Z1H6qn
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。 cciAMQhA
7、说明:添加主键: Alter table tabname add primary key(col) c=jI.=mi3
说明:删除主键: Alter table tabname drop primary key(col) YjIED,eRv
8、说明:创建索引:create [unique] index idxname on tabname(col....) p0y0T|H^
删除索引:drop index idxname sJHy=z0m
注:索引是不可更改的,想更改必须删除重新建。 bHWvKv+
9、说明:创建视图:create view viewname as select statement kj<D 4)
删除视图:drop view viewname die2<'\4%
10、说明:几个简单的基本的sql语句 :)+@qxTy
选择:select * from table1 where 范围 3q.[-.q
插入:insert into table1(field1,field2) values(value1,value2) BhE~k?$9
删除:delete from table1 where 范围 v{rK_jq
更新:update table1 set field1=value1 where 范围 ZimMjZ%4
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! VATXsD
排序:select * from table1 order by field1,field2 [desc] d6d(?"
总数:select count as totalcount from table1 qqom$H<
求和:select sum(field1) as sumvalue from table1
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平均:select avg(field1) as avgvalue from table1 G
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最大:select max(field1) as maxvalue from table1 +k(3+b$S-
最小:select min(field1) as minvalue from table1 3Ld ;zW
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11、说明:几个高级查询运算词 -RqAT 1
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A: UNION 运算符 X5oW[
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 {, *Y
B: EXCEPT 运算符 "TH-A6v1
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 j@?[vi
C: INTERSECT 运算符 LN3dp?;_{
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 7^t(RNq
注:使用运算词的几个查询结果行必须是一致的。 m9<[bEO<$
12、说明:使用外连接 9bcyPN
A、left outer join: U37?P7i's
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。 {@K2WB
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 eze(>0\f
B:right outer join: ";Ig%]
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。
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C:full outer join: m)]fJ_
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。 >~wk
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二、提升 a$ ! {Tob2
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) Y /ac}q
法一:select * into b from a where 1<>1 D15u1A
法二:select top 0 * into b from a N5an9r&z(1
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) NUNn[c
insert into b(a, b, c) select d,e,f from b; zQj%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)
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insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 H{A| ~V)
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 674oL,
4、说明:子查询(表名1:a 表名2:b) 0|>
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) v7OV;ea$
5、说明:显示文章、提交人和最后回复时间 #M9D"
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select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b \/4%[Q2QDm
6、说明:外连接查询(表名1:a 表名2:b) ^Er`{|o6u
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c |%cO"d^ri
7、说明:在线视图查询(表名1:a ) _NqT8C4C
select * from (SELECT a,b,c FROM a) T where t.a > 1; |>}0? '/]
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 @SG="L
select * from table1 where time between time1 and time2 "oXAIfU#T
select a,b,c, from table1 where a not between 数值1 and 数值2 @[kM1:G-F{
9、说明:in 的使用方法 -hR\Y2?
select * from table1 where a [not] in ('值1','值2','值4','值6') m#K%dR
10、说明:两张关联表,删除主表中已经在副表中没有的信息 {2clOUi
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) 3XlnI:w=
11、说明:四表联查问题: ?uX6X'-
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 ..... ee0>B86tE
12、说明:日程安排提前五分钟提醒 IS4K$Ac.
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 xPJJ
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13、说明:一条sql 语句搞定数据库分页 %s :
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 s]8J+8
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14、说明:前10条记录 "/Q(UV<d
select top 10 * form table1 where 范围 3N*C]
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) P:-/3
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) {ro!OuA
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 u2O^3rG-
(select a from tableA ) except (select a from tableB) except (select a from tableC) [*ovYpj^
17、说明:随机取出10条数据 si.a]k/f
select top 10 * from tablename order by newid() |b~g^4
18、说明:随机选择记录 :O+b4R+
select newid() "v(]"L
19、说明:删除重复记录 8[`<u[Iv
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) Dlf=N$BL7d
20、说明:列出数据库里所有的表名 |=}~>!!
select name from sysobjects where type='U' (ai-n,y
21、说明:列出表里的所有的 K}3"K C
select name from syscolumns where id=object_id('TableName') M &EJFpc*
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。 ;U3Vows
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 cE>/iZc
显示结果: 9,> Y
type vender pcs &0Zk3D4
电脑 A 1 rWpfAE)!
电脑 A 1 '?GZ"C2
光盘 B 2 Q09~vFBg
光盘 A 2 3CuoBb8
手机 B 3 a(T4WDl^
手机 C 3 uN0fWj]
23、说明:初始化表table1 6Q.whV%y
TRUNCATE TABLE table1 <U`Nb) &
24、说明:选择从10到15的记录 ?ML<o>OKg
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc WR EGRy
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三、技巧 qA/3uA!z
1、1=1,1=2的使用,在SQL语句组合时用的较多 ]JuB6o_L
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 0MGK3o)
如: O[B_7
if @strWhere !='' NVZNQ{
begin abP?Dj&
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere q[A3$y(
end ~M1%,]
else c}s3c
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begin irj}:f;!eF
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' O'U,|A
end urjp&L&
我们可以直接写成 -3U}
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere c2:kZxT
2、收缩数据库 g~u!,Zc
--重建索引 wk/U"@lq
DBCC REINDEX 4zbV' ]
DBCC INDEXDEFRAG q`zR 6
--收缩数据和日志 X]%4QIeS
DBCC SHRINKDB vA~hkkj{
DBCC SHRINKFILE o!0a8i
3、压缩数据库 *9^k^h(r&4
dbcc shrinkdatabase(dbname) OZ9j3Q;a$
4、转移数据库给新用户以已存在用户权限 5X|aa>/
exec sp_change_users_login 'update_one','newname','oldname' :$d 3a"]
go H}rP{`m
5、检查备份集 oC>~r1.j
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' dU n#'<g5
6、修复数据库 5|z[%x~f
ALTER DATABASE [dvbbs] SET SINGLE_USER t2<(by!
GO ]2
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DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK 1h{_v!X
GO Ut@)<N
ALTER DATABASE [dvbbs] SET MULTI_USER mt7:`-
GO Q&{5.}L
7、日志清除 k Er7,c
SET NOCOUNT ON aW5~z^I
DECLARE @LogicalFileName sysname, Pw1H)<X
@MaxMinutes INT, Cvy;O~)
@NewSize INT 1N*~\rV*?
USE tablename -- 要操作的数据库名 VQ`O;n6/`
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 2Z |kf9
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 6Wp:W1E{`
@NewSize = 1 -- 你想设定的日志文件的大小(M) e&nw&9vo
-- Setup / initialize S_=u v)%a
DECLARE @OriginalSize int #{sb>^BF
SELECT @OriginalSize = size ~coG8r"o
FROM sysfiles -n-X/M
WHERE name = @LogicalFileName cd#TKmh7re
SELECT 'Original Size of ' + db_name() + ' LOG is ' + qI:wm=
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + so?1lG
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' nK$m:=
FROM sysfiles f}4h}Cq
WHERE name = @LogicalFileName /8R1$7
CREATE TABLE DummyTrans xa:P(x3[
(DummyColumn char (8000) not null) 9X~^w_cdk
DECLARE @Counter INT, cj)~7 WF
@StartTime DATETIME, -)GfSk
@TruncLog VARCHAR(255) >LSA?dy!?
SELECT @StartTime = GETDATE(),
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@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' @ck2j3J/
DBCC SHRINKFILE (@LogicalFileName, @NewSize) #.RI9B
EXEC (@TruncLog) usip>y
-- Wrap the log if necessary. 7Ll(,i<,C
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired U_?RN)>j
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) ^C{a'
AND (@OriginalSize * 8 /1024) > @NewSize h2]Od(^[
BEGIN -- Outer loop. >v{m^|QqB
SELECT @Counter = 0 l=yO]a\QZ
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) }e$);A|
BEGIN -- update ~+Y;jAdU
INSERT DummyTrans VALUES ('Fill Log') O%I'
DELETE DummyTrans =9M-N?cV
SELECT @Counter = @Counter + 1 }m?L/Y'}
END n3w2&
EXEC (@TruncLog) UJI1n?~
END ]_h"2|
SELECT 'Final Size of ' + db_name() + ' LOG is ' + C-7.Sa
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + q0<g#jK
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' .B@;ch,
FROM sysfiles -3Ffk:
WHERE name = @LogicalFileName J=sQ].EK
DROP TABLE DummyTrans %`~8j H@
SET NOCOUNT OFF ]=/f`
8、说明:更改某个表
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exec sp_changeobjectowner 'tablename','dbo' VybiuP
9、存储更改全部表 #f[yp=uI:
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch -V\33cA
@OldOwner as NVARCHAR(128), 3 . @W.GG8
@NewOwner as NVARCHAR(128) ?#W>^Za=
AS X(8]9
DECLARE @Name as NVARCHAR(128) a*=e 3nS
DECLARE @Owner as NVARCHAR(128) |YH1q1l
DECLARE @OwnerName as NVARCHAR(128) 2oNlQiE_
DECLARE curObject CURSOR FOR :Qf^@TS}O
select 'Name' = name, 9:P)@UF
'Owner' = user_name(uid) *yB!^O
from sysobjects I(2ID +
where user_name(uid)=@OldOwner 7|2:;5:U
order by name j"f]pzg&
OPEN curObject /%.K`BMN
FETCH NEXT FROM curObject INTO @Name, @Owner I%%$O'S
WHILE(@@FETCH_STATUS=0) S"lcePN
BEGIN @x)z" )>
if @Owner=@OldOwner -wY6da*.W
begin LnBkd:>}
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ,7eN m>$
exec sp_changeobjectowner @OwnerName, @NewOwner Bq'hk<ns[
end zj8;ENhEI
-- select @name,@NewOwner,@OldOwner |u03~L9G
FETCH NEXT FROM curObject INTO @Name, @Owner *FO']D
END rt"\\sOlMB
close curObject ?9AByg
deallocate curObject aFhsRE?YC=
GO _I2AJn`#
10、SQL SERVER中直接循环写入数据 ]E`DG
declare @i int o'W &gkb9
set @i=1 F7mzBrz
while @i<30
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begin D|OX]3~
insert into test (userid) values(@i) $)kIYM&
set @i=@i+1 ?vvjwys@
end ?onZ:s2
小记存储过程中经常用到的本周,本月,本年函数 Dtn|$g,
Dateadd(wk,datediff(wk,0,getdate()),-1) t0?\5q
Dateadd(wk,datediff(wk,0,getdate()),6) yfYAA*S!z
Dateadd(mm,datediff(mm,0,getdate()),0) w)hJ0k
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) %2V_%KA
Dateadd(yy,datediff(yy,0,getdate()),0) T?Gi;ld7
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 16xM?P
上面的SQL代码只是一个时间段 IA''-+9
Dateadd(wk,datediff(wk,0,getdate()),-1) BoFJ8Ukq|
Dateadd(wk,datediff(wk,0,getdate()),6) ^lbOv}C*
就是表示本周时间段. *S*;rLH9c
下面的SQL的条件部分,就是查询时间段在本周范围内的: ZcIwyh(`
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) >a
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而在存储过程中 /SSl$
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) _8t{4C
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) H!HkXm"