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。 *l)_&p
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一、基础 ;ug&v
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1、说明:创建数据库 T4]/w|?G
CREATE DATABASE database-name P6u9Ngay
2、说明:删除数据库 T&oY:1D,g
drop database dbname [ %cW ?@
3、说明:备份sql server s{(aW5$!s
--- 创建 备份数据的 device cV\(Z6u
USE master xdFm-_\-
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' -y5^xR
--- 开始 备份 Ur6UE2
BACKUP DATABASE pubs TO testBack 8`v+yHjG
4、说明:创建新表 !trt]?*-
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) ^HgQ"dD
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根据已有的表创建新表: <1YINkRz
A:create table tab_new like tab_old (使用旧表创建新表) :1^
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B:create table tab_new as select col1,col2... from tab_old definition only $A;jl`ng
5、说明:删除新表 UOJx-o!c?
drop table tabname B8F.}M-!
6、说明:增加一个列 |L}zB,
Alter table tabname add column col type $sTbFY
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 ~Z9Eb|B
7、说明:添加主键: Alter table tabname add primary key(col) lr'h
说明:删除主键: Alter table tabname drop primary key(col) !8 lG"l|,l
8、说明:创建索引:create [unique] index idxname on tabname(col....) cfBq/2I
删除索引:drop index idxname
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注:索引是不可更改的,想更改必须删除重新建。 0"ksNnxK
9、说明:创建视图:create view viewname as select statement ;R|i@[(J
删除视图:drop view viewname J3fk3d`2
10、说明:几个简单的基本的sql语句 =
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选择:select * from table1 where 范围 /{>$E>N;
插入:insert into table1(field1,field2) values(value1,value2) cKJf0S:cx-
删除:delete from table1 where 范围 cXU8}>qY7
更新:update table1 set field1=value1 where 范围 w#vSZbh
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! Zyt,D|eWj
排序:select * from table1 order by field1,field2 [desc] HY0q!.qog
总数:select count as totalcount from table1 hiq7e*Nsb
求和:select sum(field1) as sumvalue from table1 DDxbIkt
平均:select avg(field1) as avgvalue from table1
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最大:select max(field1) as maxvalue from table1 YT'G#U1x~
最小:select min(field1) as minvalue from table1 a"SH_+T{
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11、说明:几个高级查询运算词 }{T9`^V:h
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A: UNION 运算符 Jmrs@
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。 8mj Pa^A
B: EXCEPT 运算符 v%v(-, _q
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。 '#RzX8|v<
C: INTERSECT 运算符 K2$ fKju
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。 kW#,o 9f\
注:使用运算词的几个查询结果行必须是一致的。 #hG0{_d7
12、说明:使用外连接 C))5,aX
A、left outer join: `B6*wE-|
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。 7ss Y*1b
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 ,I6jfXI4
B:right outer join: M8dv
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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。 <Hd8Jd4f
C:full outer join: iO1ir+B\
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。 2-!OflkoM0
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二、提升 Tzr_K
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) Loz5[L
法一:select * into b from a where 1<>1 gZA[Sq
法二:select top 0 * into b from a Hdvtgss!
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) HYcLXh vgu
insert into b(a, b, c) select d,e,f from b; G>Fk
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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) \WS2g"(
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 }L
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例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. !dnCrR
4、说明:子查询(表名1:a 表名2:b) 9
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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) b-?wJSf|
5、说明:显示文章、提交人和最后回复时间 eS#kDa/ %
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 5Ku=Xzvq
6、说明:外连接查询(表名1:a 表名2:b)
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select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c krqz;q-p~
7、说明:在线视图查询(表名1:a ) S!+c1q:
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select * from (SELECT a,b,c FROM a) T where t.a > 1; r-^FM~Jp
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 ?,s]5
select * from table1 where time between time1 and time2 yP$@~L[!
select a,b,c, from table1 where a not between 数值1 and 数值2
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9、说明:in 的使用方法 :j(e+A1@
select * from table1 where a [not] in ('值1','值2','值4','值6') -R%T Dx
10、说明:两张关联表,删除主表中已经在副表中没有的信息 9mE6Cp.Wv
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) LSewMj
11、说明:四表联查问题: pK` 1pfih
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... WX"iDz.
12、说明:日程安排提前五分钟提醒 r<'ni
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 G47(LE"2b
13、说明:一条sql 语句搞定数据库分页 !8g419Yg
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 M3XG s|gw
14、说明:前10条记录 6HroKu
select top 10 * form table1 where 范围 9S'u1%
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) 6U .A/8z
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) OaTnQ|*
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 G5WQTMzf&
(select a from tableA ) except (select a from tableB) except (select a from tableC) G^r`)ND
17、说明:随机取出10条数据 m(>MP/
select top 10 * from tablename order by newid() UY>[
18、说明:随机选择记录 ^}SP,lg'
select newid() 4X-" yQ<U
19、说明:删除重复记录 CdBpz/
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) bG0
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20、说明:列出数据库里所有的表名 87!D@Xn
select name from sysobjects where type='U' ;X_bDiG$
21、说明:列出表里的所有的 I+oe{#:.
select name from syscolumns where id=object_id('TableName') iGq%|o>
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。 FOPfob[
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 F
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显示结果: vYFtw L`
type vender pcs @%lkRU)
电脑 A 1 gB
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电脑 A 1 1JQ5bB"
光盘 B 2 kM6i{{Q
光盘 A 2 J#.f%VJ
手机 B 3 Ky0}phGRu
手机 C 3 2xLEB&
23、说明:初始化表table1 3Pu8IXW
TRUNCATE TABLE table1 # &,W x
24、说明:选择从10到15的记录 =Bg $OX
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc #B!|sXC
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三、技巧 ?"F9~vx&G
1、1=1,1=2的使用,在SQL语句组合时用的较多 ol0i^d*9F
"where 1=1" 是表示选择全部 "where 1=2"全部不选, ^ps6\>=0cW
如: &Fiesi!tET
if @strWhere !='' o3"Nxq"U
begin (]E0fjk
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere #fYRsVQ
end K`=9"v'f+
else HVJqDF
begin a8WWFAC[
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' }/w]+f*
end m?<^b_a}
我们可以直接写成 ~8 B]
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere f+cN'jH
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2、收缩数据库 XE>w&
--重建索引 LR "=(
DBCC REINDEX XF&_**0n
DBCC INDEXDEFRAG `@q\R-`
--收缩数据和日志 ^B_SAZ&%%
DBCC SHRINKDB kYhV1I
DBCC SHRINKFILE )[S#:PP
3、压缩数据库 r>e1IG
dbcc shrinkdatabase(dbname) C669:%
4、转移数据库给新用户以已存在用户权限 ,i jB3J
exec sp_change_users_login 'update_one','newname','oldname' }qw->+nD
go A"B#t"
5、检查备份集 l4gF.-.GYF
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 4#Xz-5v
6、修复数据库 !/a![Ne
ALTER DATABASE [dvbbs] SET SINGLE_USER vbD""
GO "S]G+/I|iw
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK kwXUjnp
GO $>8O2p7W
ALTER DATABASE [dvbbs] SET MULTI_USER >\!G43Q=
GO /Rf,Rjs
7、日志清除 (@ 1>G
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SET NOCOUNT ON CnpQdI
DECLARE @LogicalFileName sysname, lak,lDt]
@MaxMinutes INT, %[4u #G`
@NewSize INT
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USE tablename -- 要操作的数据库名 ur:8`+"
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SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 ?f$U8A4lp
@MaxMinutes = 10, -- Limit on time allowed to wrap log. -Qn l)JB
@NewSize = 1 -- 你想设定的日志文件的大小(M) 4VHWoN"U
-- Setup / initialize VFrp7;z43
DECLARE @OriginalSize int v8YF+N
SELECT @OriginalSize = size }4g$aTc
FROM sysfiles J(G-c5&=
WHERE name = @LogicalFileName y|0!sNg
SELECT 'Original Size of ' + db_name() + ' LOG is ' + <vE|QxpR
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + QuP)j1"X
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' Z2L7US-
FROM sysfiles MQQQaD:v
WHERE name = @LogicalFileName NEUr w/
CREATE TABLE DummyTrans e^<'H
(DummyColumn char (8000) not null) gyQPQ;"H$2
DECLARE @Counter INT, !4a#);`G
@StartTime DATETIME, S"VO@)d
@TruncLog VARCHAR(255) G|*&owJ
SELECT @StartTime = GETDATE(), 67;6nXG0K
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' l^XOW- ;u
DBCC SHRINKFILE (@LogicalFileName, @NewSize) No8-Hm
EXEC (@TruncLog) d
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-- Wrap the log if necessary. Bq;GO
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired \11+~
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) f|=u{6
AND (@OriginalSize * 8 /1024) > @NewSize QE8`nMf
BEGIN -- Outer loop. m2H?VY.^K
SELECT @Counter = 0 g[R4/]K^$
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) |ZM>UJ
BEGIN -- update aX~Jk >a0
INSERT DummyTrans VALUES ('Fill Log') V.9p4k`
DELETE DummyTrans I94-#*~I
SELECT @Counter = @Counter + 1 jo?[M
END ~F53{qxV
EXEC (@TruncLog) l}iQ0v@
END 3GNcnb
SELECT 'Final Size of ' + db_name() + ' LOG is ' + z9:yt5ar
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + (&1.!R[X
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ]bAVOKm-
FROM sysfiles =]5f\f6
WHERE name = @LogicalFileName Sgr. V)
DROP TABLE DummyTrans `rXb:P7m{j
SET NOCOUNT OFF t 9t
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8、说明:更改某个表 #1C]ZV] B
exec sp_changeobjectowner 'tablename','dbo' :.tL~%
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9、存储更改全部表 Qcks:|5
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch @U4hq7xzV2
@OldOwner as NVARCHAR(128), 1{5t.
@NewOwner as NVARCHAR(128) )"?eug}D
AS d&+0JI<
DECLARE @Name as NVARCHAR(128) Ud Vf/PGx
DECLARE @Owner as NVARCHAR(128) jU kxA7 }}
DECLARE @OwnerName as NVARCHAR(128) 1l/t|M^I
DECLARE curObject CURSOR FOR W
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select 'Name' = name, '=O1n H<
'Owner' = user_name(uid) 8{]nS8i
from sysobjects +~BP~
where user_name(uid)=@OldOwner 7x=4P|(\}
order by name @)x*6 2r+
OPEN curObject >gs_Bzy]
FETCH NEXT FROM curObject INTO @Name, @Owner ^Zp
WHILE(@@FETCH_STATUS=0) 5]GgjQ
BEGIN Zwz co
if @Owner=@OldOwner x N7sFSV@
begin i6A9|G$H
set @OwnerName = @OldOwner + '.' + rtrim(@Name) eM
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exec sp_changeobjectowner @OwnerName, @NewOwner z@J>A![m
end kt0xR)gU
-- select @name,@NewOwner,@OldOwner eX>*}pI
FETCH NEXT FROM curObject INTO @Name, @Owner TqL+^:cq
END wx[m-\
close curObject ~#4FL<W
deallocate curObject 8MI8~
GO uO-|?{29
10、SQL SERVER中直接循环写入数据 ,[T/O\k
declare @i int \m~p;B
set @i=1 *sZH3:
while @i<30 Z:<an+v|5
begin -)B_o#2=2
insert into test (userid) values(@i) gwsIzYV
set @i=@i+1 PqL.^
end Qclq^|O0
小记存储过程中经常用到的本周,本月,本年函数 Y8^WuN$
Dateadd(wk,datediff(wk,0,getdate()),-1) j#2EQ
Dateadd(wk,datediff(wk,0,getdate()),6) RjH68=n
Dateadd(mm,datediff(mm,0,getdate()),0) dWQB1Y*N
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) !V(r
p80
Dateadd(yy,datediff(yy,0,getdate()),0) >d=pl}-kOQ
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) Ue60Mf
上面的SQL代码只是一个时间段 ;2\6U;
Dateadd(wk,datediff(wk,0,getdate()),-1) W8$0y2
Dateadd(wk,datediff(wk,0,getdate()),6) "/RMIS
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就是表示本周时间段. JBLUX,
下面的SQL的条件部分,就是查询时间段在本周范围内的: <&3aP}
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ~".@;Q
而在存储过程中 Zhv%mUj~
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) -|^)8
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) GA$fueiQNs