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。 cHk)i
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一、基础 ~XmLX)vO/
1、说明:创建数据库 /$p6'1P8
CREATE DATABASE database-name R1$:~p2m
2、说明:删除数据库
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drop database dbname
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3、说明:备份sql server ,tu.2VQc@
--- 创建 备份数据的 device |$
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USE master #ZrHsfP
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' ) iN/ua
--- 开始 备份 >E{";C)
BACKUP DATABASE pubs TO testBack 7Bd-!$j+
4、说明:创建新表 KJaXg;,H
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) yj.7'{mA
根据已有的表创建新表: 7E79-r&n
A:create table tab_new like tab_old (使用旧表创建新表) fy@<&U5rg
B:create table tab_new as select col1,col2... from tab_old definition only %2{%Obp'
5、说明:删除新表 |#cm`v
drop table tabname ^Xq 6:
6、说明:增加一个列 %UERc{~o*,
Alter table tabname add column col type e9U9Uu[
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。 heC/\@B
7、说明:添加主键: Alter table tabname add primary key(col) $m-2HhqZ
说明:删除主键: Alter table tabname drop primary key(col) {ix?Brq/
8、说明:创建索引:create [unique] index idxname on tabname(col....) 9 %I?).5
删除索引:drop index idxname SPY|K
注:索引是不可更改的,想更改必须删除重新建。 mQ|v26R
9、说明:创建视图:create view viewname as select statement S p;G'*g
删除视图:drop view viewname &&8IU;J
10、说明:几个简单的基本的sql语句 `n@*{J8
选择:select * from table1 where 范围 6"J?
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插入:insert into table1(field1,field2) values(value1,value2) q!u~jI9j
删除:delete from table1 where 范围 n%o5kVx0
更新:update table1 set field1=value1 where 范围 >\P@^ h]
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! SVh 7zh
排序:select * from table1 order by field1,field2 [desc]
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总数:select count as totalcount from table1 !W}9no
求和:select sum(field1) as sumvalue from table1 "AsKlKz{B
平均:select avg(field1) as avgvalue from table1 #Oc]
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最大:select max(field1) as maxvalue from table1 j2StXq3
最小:select min(field1) as minvalue from table1 keX,d#
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11、说明:几个高级查询运算词 fPR1f~r
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A: UNION 运算符 iXVe.n
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。 1AM!8VR2
B: EXCEPT 运算符 $!-c-0ub
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 R6kD=JY/!
C: INTERSECT 运算符 r") `Ph@yp
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 "!ug_'VW
注:使用运算词的几个查询结果行必须是一致的。 [6%VRqY
12、说明:使用外连接 ^cP!\E-^
A、left outer join: ;Q OBBF3HG
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 9.gXzPH
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c
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B:right outer join: =JK@z
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 g9}DnCT*.
C:full outer join: /_AnP
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 4C61GB?Vy
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二、提升 *rs5]U<
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) c1k/UcEcg~
法一:select * into b from a where 1<>1 M3c$=>
法二:select top 0 * into b from a e.7EU
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) IEsEdw]aZE
insert into b(a, b, c) select d,e,f from b; M/>7pZW
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) s
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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 8D3OOab
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. mS$j?>m
4、说明:子查询(表名1:a 表名2:b) tl,.fjZn
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) =[cS0Sy
5、说明:显示文章、提交人和最后回复时间 (|:M&Cna]
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b vNV/eB8#S
6、说明:外连接查询(表名1:a 表名2:b) pfA|I*`XV
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c v&Yi
7、说明:在线视图查询(表名1:a ) Ai=se2
select * from (SELECT a,b,c FROM a) T where t.a > 1; Pq;U&,
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 )wam8k5
select * from table1 where time between time1 and time2 &:9cAIe]H
select a,b,c, from table1 where a not between 数值1 and 数值2 =.f-w0V
9、说明:in 的使用方法 ;c-(ObSm
select * from table1 where a [not] in ('值1','值2','值4','值6') 4o
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10、说明:两张关联表,删除主表中已经在副表中没有的信息 p*4':TFuD;
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) :dl]h&C^
11、说明:四表联查问题: I7 |Pi[e
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... ~?4PBq
12、说明:日程安排提前五分钟提醒 ^84G%)`&
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 rb5~XnJk
13、说明:一条sql 语句搞定数据库分页 \o}xF@sM5
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 z;{iM/Xe
14、说明:前10条记录 TN!j13,
select top 10 * form table1 where 范围 U\4g#!qj
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) TJ_$vI
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) c}Ft^Il
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 OE_XCZ!5P
(select a from tableA ) except (select a from tableB) except (select a from tableC) S!jTyY7e
17、说明:随机取出10条数据 /32Fy`KV
select top 10 * from tablename order by newid() X@+{5%
18、说明:随机选择记录 n7B7 m,@1
select newid() $2oTkOA
19、说明:删除重复记录 "bFTk/
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) &gVN&
20、说明:列出数据库里所有的表名 we~[ ]
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select name from sysobjects where type='U' H*RC@O_hv
21、说明:列出表里的所有的 0%9 q8M;
select name from syscolumns where id=object_id('TableName') zT=Ho
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。 j"ThEx0
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 Y;dz,}re
显示结果: 2iY3Lsna
type vender pcs f2Klt6"9
电脑 A 1 \\r)Ue]
电脑 A 1 5,3'=mA6
光盘 B 2 hm84Aq= f
光盘 A 2 q+H%)kF
手机 B 3 6]V4muz#c
手机 C 3 8##-EN;ag
23、说明:初始化表table1 #a/5SZP
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TRUNCATE TABLE table1 <C1H36p
24、说明:选择从10到15的记录 C]O(T2l{l
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc RkH W
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三、技巧 R0P
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1、1=1,1=2的使用,在SQL语句组合时用的较多 D"Bl:W'?j
"where 1=1" 是表示选择全部 "where 1=2"全部不选, _GXk0Ia3`
如: =e/9&993
if @strWhere !='' -V-RP;">
begin j`JMeCG=Ee
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere V, Z|tB^
end iZ#!O*>
else ]{)a,c NG
begin 4,bv)Im+ `
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' Ttu2 skcv
end sv: 9clJ
我们可以直接写成 nno}e/zqf
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere hv`~?n)D66
2、收缩数据库 &vo--V1|
--重建索引 9v;Vv0k_
DBCC REINDEX Od)Uv1
DBCC INDEXDEFRAG H{@Yo\J
--收缩数据和日志 #o=y?(
DBCC SHRINKDB j#X.KM
DBCC SHRINKFILE ~+Rc}K
3、压缩数据库 eV2W{vuI
dbcc shrinkdatabase(dbname) TTeH`
4、转移数据库给新用户以已存在用户权限 8;d:-Cp
exec sp_change_users_login 'update_one','newname','oldname' W3]_m8,Z
go R?GDJ3
5、检查备份集 \kp8S'qVo
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ;\a
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6、修复数据库 %7"q"A r[
ALTER DATABASE [dvbbs] SET SINGLE_USER TC@s
GO Ee)T1~;W
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK ]9YJ,d@J
GO $yn];0$J
ALTER DATABASE [dvbbs] SET MULTI_USER 8UW^"4
GO J ][T"K
7、日志清除 q-
SET NOCOUNT ON HKU~UTRnZ
DECLARE @LogicalFileName sysname, nim*/LC[:
@MaxMinutes INT, %z/hf
@NewSize INT ~k\fhx
USE tablename -- 要操作的数据库名 ;
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SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 =[H;orMr
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 6TQoqH8@U
@NewSize = 1 -- 你想设定的日志文件的大小(M) UR%/MV
-- Setup / initialize -d~4A
DECLARE @OriginalSize int FK:;e
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SELECT @OriginalSize = size _g+JA3sIJ
FROM sysfiles Vu)4dD!
WHERE name = @LogicalFileName |*oZ_gI
SELECT 'Original Size of ' + db_name() + ' LOG is ' + WB?jRYp
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + OP~HdocB
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' di?K"Z>
FROM sysfiles G^~k)6v=m
WHERE name = @LogicalFileName x^HGVWw_
CREATE TABLE DummyTrans D2<fw#
(DummyColumn char (8000) not null) ^"VJd[Hn
DECLARE @Counter INT, W}3.E "K
@StartTime DATETIME, /,89p&h
@TruncLog VARCHAR(255) 1%EBd%`#
SELECT @StartTime = GETDATE(), $&y%=-] |
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' T?:Rdo!:u
DBCC SHRINKFILE (@LogicalFileName, @NewSize) NgADKrDU
EXEC (@TruncLog) $LKIT0
-- Wrap the log if necessary. (*Z)(O*z
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired hLI`If/+K
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) {\S+#W\
AND (@OriginalSize * 8 /1024) > @NewSize m`v2: S}
BEGIN -- Outer loop. #Vl 0.l3
SELECT @Counter = 0 I, -hf=-
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) VLS0XKI)
BEGIN -- update V `b2TS
INSERT DummyTrans VALUES ('Fill Log') M3J#'%$
DELETE DummyTrans ?HTjmIb
SELECT @Counter = @Counter + 1 :?k>HQe
END &)8:h+&Z
EXEC (@TruncLog) Wl;.%.]>
END u6M.'
SELECT 'Final Size of ' + db_name() + ' LOG is ' + }E+!91't.^
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + V_C-P[2~
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ^@I
FROM sysfiles , R'@%,/
WHERE name = @LogicalFileName 3;)>Fs;
DROP TABLE DummyTrans :}yi-/_8!
SET NOCOUNT OFF |M>eEE*F<
8、说明:更改某个表 6BY-^"W5`
exec sp_changeobjectowner 'tablename','dbo' !(mjyr
9、存储更改全部表 wAX1l*`
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch XUM!Qv
@OldOwner as NVARCHAR(128), VcAue!MN
@NewOwner as NVARCHAR(128) *YW/_
AS stG~AC
DECLARE @Name as NVARCHAR(128) 8;z6=.4xtg
DECLARE @Owner as NVARCHAR(128) IYqBQnX}oM
DECLARE @OwnerName as NVARCHAR(128) ZtV9&rd7
DECLARE curObject CURSOR FOR ]Oh@,V8
select 'Name' = name, K)-U1JE7
'Owner' = user_name(uid) ln$&``L
from sysobjects /d0K7F
where user_name(uid)=@OldOwner M8INk,si
order by name 4oK?-|=?
OPEN curObject .clP#r{U
FETCH NEXT FROM curObject INTO @Name, @Owner vh"R'o
WHILE(@@FETCH_STATUS=0) *Nw&_<\9Q
BEGIN W!%]_I!&K
if @Owner=@OldOwner ` BDLW%aL
begin cmBB[pk\
set @OwnerName = @OldOwner + '.' + rtrim(@Name) ^:K3vC[h;c
exec sp_changeobjectowner @OwnerName, @NewOwner un shH <
end So{x]x:f
-- select @name,@NewOwner,@OldOwner 'Hc-~l>D
FETCH NEXT FROM curObject INTO @Name, @Owner y]2qd35u_A
END D5$wTI
close curObject P.6nA^hXB
deallocate curObject 5 elw~u
GO n/DP>U$I&
10、SQL SERVER中直接循环写入数据 N<f"]
declare @i int @WJgWJm
set @i=1 /nyUG^5#{
while @i<30 4S,`bnmB
begin ^cV;~&|.Xk
insert into test (userid) values(@i) [!!o-9b
set @i=@i+1 if}-_E<F
end wkP#Z"A0~
小记存储过程中经常用到的本周,本月,本年函数 (2$(
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Dateadd(wk,datediff(wk,0,getdate()),-1) &?VQ,+[<
Dateadd(wk,datediff(wk,0,getdate()),6) tDSJpW'd
Dateadd(mm,datediff(mm,0,getdate()),0) kV?y0J.
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 9w"h
Dateadd(yy,datediff(yy,0,getdate()),0) 7Ok;Lt!x
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) 2}YOcnB
上面的SQL代码只是一个时间段 aJYgzr,
Dateadd(wk,datediff(wk,0,getdate()),-1) z)'M k[
Dateadd(wk,datediff(wk,0,getdate()),6) "vXxv'0\f
就是表示本周时间段. Tg!i%v(-t
下面的SQL的条件部分,就是查询时间段在本周范围内的: W"):-Wq
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) !O-T0O
而在存储过程中 I'PeN0T
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select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) F_Z- 8>P
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) N U|d