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。 x%>
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一、基础 O9h+Q\0\W
1、说明:创建数据库 gPC@Yy
CREATE DATABASE database-name W0`Gc
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2、说明:删除数据库 H: {7X1bV
drop database dbname Xh+ia#K
3、说明:备份sql server hZ\+FOx;
--- 创建 备份数据的 device 8nNsrat
USE master C'mL&
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' H}0dd"
--- 开始 备份 u=+q$Q]
BACKUP DATABASE pubs TO testBack c9Es%@]
4、说明:创建新表 =([av7
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) =H5\$&xj4.
根据已有的表创建新表: alFjc.~}
A:create table tab_new like tab_old (使用旧表创建新表) c@m5~
B:create table tab_new as select col1,col2... from tab_old definition only ub?K,
5、说明:删除新表 T~8
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drop table tabname t2{~bzq1X
6、说明:增加一个列 /uqu32;o
Alter table tabname add column col type %g"eV4j
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 "dh:-x6
7、说明:添加主键: Alter table tabname add primary key(col) )hKS0`$|
说明:删除主键: Alter table tabname drop primary key(col) }OShT+xeX
8、说明:创建索引:create [unique] index idxname on tabname(col....) j8 ,n7!G
删除索引:drop index idxname >um!Eo
注:索引是不可更改的,想更改必须删除重新建。 V L( <
9、说明:创建视图:create view viewname as select statement V,7%1TZ:
删除视图:drop view viewname mz7l'4']+
10、说明:几个简单的基本的sql语句 wwd'0P`/
选择:select * from table1 where 范围 2h^WYpCm
插入:insert into table1(field1,field2) values(value1,value2) e&It
删除:delete from table1 where 范围 rJfqA@
更新:update table1 set field1=value1 where 范围 pb;")Q'
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! (zo^Nn9VJ
排序:select * from table1 order by field1,field2 [desc] b
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总数:select count as totalcount from table1 !cEG}(|h
求和:select sum(field1) as sumvalue from table1 $A\m>*@
平均:select avg(field1) as avgvalue from table1 ekSY~z=/u
最大:select max(field1) as maxvalue from table1 i^z`"3#LE
最小:select min(field1) as minvalue from table1 wVK*P
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11、说明:几个高级查询运算词 }k$4/7ri
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A: UNION 运算符 eo]#sf@\0
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 0Ce]V,i6C>
B: EXCEPT 运算符 ik1tidw
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 obClBO)@Y
C: INTERSECT 运算符 EmVuwphv
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 2-If]Fc
注:使用运算词的几个查询结果行必须是一致的。 ]hw-Bu\{
12、说明:使用外连接 p
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A、left outer join: YhKZ|@
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 NY
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c FpV`#6i7
B:right outer join: YrI|gz)
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 R""%F#4XJ2
C:full outer join: %uESrc-;
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 *e.*=$
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二、提升 g;p)n
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) H3/caN:
法一:select * into b from a where 1<>1 1cN')"
法二:select top 0 * into b from a h=VqxGC&
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) h#YD~!aJ
insert into b(a, b, c) select d,e,f from b; ^y.UbI
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) KpZ:Nh$
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 mS=r(3#
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. _cqy`p@"
4、说明:子查询(表名1:a 表名2:b) }6zbT-i
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) Iq5pAHm>M6
5、说明:显示文章、提交人和最后回复时间 b}z`BRCc
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 6Y*;{\Rd
6、说明:外连接查询(表名1:a 表名2:b) 70W"G
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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 t={0(
7、说明:在线视图查询(表名1:a ) q%3<Juq~$
select * from (SELECT a,b,c FROM a) T where t.a > 1; OmMX$YID
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 c-]fKj7
select * from table1 where time between time1 and time2 _ *(bmJM
select a,b,c, from table1 where a not between 数值1 and 数值2 gvavs+H%
9、说明:in 的使用方法 E$\~lcq
select * from table1 where a [not] in ('值1','值2','值4','值6') 8^ep/ b&|
10、说明:两张关联表,删除主表中已经在副表中没有的信息 lvSdY(8
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) *MM#Z?mP
11、说明:四表联查问题: >=,uau7
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 ..... F#r#}.B='U
12、说明:日程安排提前五分钟提醒 X~U >LLr
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 `x8Bn"
13、说明:一条sql 语句搞定数据库分页 8QgA@y"
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 xh9qg0d
14、说明:前10条记录 %|Qw9sbd
select top 10 * form table1 where 范围 Y>6.t"?Q^
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.) *7gT}O;p 5
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) u:P~j
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 |^n3{m
(select a from tableA ) except (select a from tableB) except (select a from tableC) !>.vh]8g
17、说明:随机取出10条数据 nS.G~c|
select top 10 * from tablename order by newid() /MTf0^9
18、说明:随机选择记录 Fe=8O ^\
select newid() qt?*MyfV
19、说明:删除重复记录 ?Hz2-Cn
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) &_-](w`
20、说明:列出数据库里所有的表名 L K7Xw3
select name from sysobjects where type='U' , |E$'
21、说明:列出表里的所有的 HxwlYx,4
select name from syscolumns where id=object_id('TableName') $xW**&
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 .J.vC1 4gi
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type wrv5V M}
显示结果: W:s@L#-
type vender pcs **;p(CI
电脑 A 1 7}
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电脑 A 1 eD#XDK
光盘 B 2 [I+9dSM1t
光盘 A 2
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手机 B 3 _9If/RD
手机 C 3 j'rS&BIG
23、说明:初始化表table1 m2bDHQ+
TRUNCATE TABLE table1 6qp5Xt+
24、说明:选择从10到15的记录 I44s(G1jl
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc %_)zWlN
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三、技巧 JSVeU54T^<
1、1=1,1=2的使用,在SQL语句组合时用的较多 ^$?qT60%d|
"where 1=1" 是表示选择全部 "where 1=2"全部不选, L:f)i,S"5q
如: :h5J r8
if @strWhere !='' pA4 ,@O
begin Q+[ .Y&
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere &y.dmW
end a-0cN 9
else C8b''9t.
begin ?[1SiJT
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' +oy*Kxs7
end ;Rnhe_A.
我们可以直接写成 QApyP CH
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere LsTffIP
2、收缩数据库 EQ
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--重建索引 Ob@Hng%v
DBCC REINDEX
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DBCC INDEXDEFRAG @z,*K_AKr
--收缩数据和日志 KFhG (
DBCC SHRINKDB wyQb5n2`;~
DBCC SHRINKFILE V'wi ^gq
3、压缩数据库 K&`Awv
dbcc shrinkdatabase(dbname) ohZx03
4、转移数据库给新用户以已存在用户权限 x7ATI[b[
exec sp_change_users_login 'update_one','newname','oldname' NPU^)B
go S7sb7c'4 k
5、检查备份集 \9m*(_Qf
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ?Myh7
6、修复数据库 O.\h'3C
ALTER DATABASE [dvbbs] SET SINGLE_USER f\o
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GO /&s}<BMHU
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK *g7DPN$aQ
GO gY5l.&
ALTER DATABASE [dvbbs] SET MULTI_USER o0Gx%99'
GO ;sQbn|=e"
7、日志清除 @EZ>f5IO+
SET NOCOUNT ON C3"&sdLb$
DECLARE @LogicalFileName sysname, $G";2(-k
@MaxMinutes INT, gA:TL{X0
@NewSize INT bx;f`8SN
USE tablename -- 要操作的数据库名 qu{mqkfN>
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 J_"3UZ~&
@MaxMinutes = 10, -- Limit on time allowed to wrap log. {BOLPE-
@NewSize = 1 -- 你想设定的日志文件的大小(M) rz
-- Setup / initialize &?<AwtNN
DECLARE @OriginalSize int _Z#eS/,O@
SELECT @OriginalSize = size 8&(-8
FROM sysfiles 4XG]z_+I
WHERE name = @LogicalFileName VXC4%
SELECT 'Original Size of ' + db_name() + ' LOG is ' + %$n02"@
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + dr]&kqm
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' &HF]\`RNr
FROM sysfiles _}=E^/;(
WHERE name = @LogicalFileName i^g~~h
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CREATE TABLE DummyTrans zO.6WJ
(DummyColumn char (8000) not null) Rc9<^g`
DECLARE @Counter INT, mK\aI
@StartTime DATETIME, ;'1Apy
@TruncLog VARCHAR(255) /H&aMk}J@y
SELECT @StartTime = GETDATE(), myvh@@N
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' >>V&yJ_
DBCC SHRINKFILE (@LogicalFileName, @NewSize) Q_}n%P:u
EXEC (@TruncLog) j
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-- Wrap the log if necessary. <94WZ?{p
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired ]P3[.$z
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) P\(30
AND (@OriginalSize * 8 /1024) > @NewSize LknVqZ|k
BEGIN -- Outer loop. iZ Ta>@
SELECT @Counter = 0 bXvbddu)}
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) ,}7_[b)&V
BEGIN -- update 1uM/2sX
INSERT DummyTrans VALUES ('Fill Log') ua#K>sur.
DELETE DummyTrans otnV-7)@
SELECT @Counter = @Counter + 1 EA yukM2
END p7 [(z
EXEC (@TruncLog) (j N]OE^
END NsmVd dj
SELECT 'Final Size of ' + db_name() + ' LOG is ' + ,"H?hFQ
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + <!!nI%NC
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' )%#?3X^sI
FROM sysfiles aL)$b
WHERE name = @LogicalFileName x5vzPh`
DROP TABLE DummyTrans uBRw>"c_*8
SET NOCOUNT OFF 6Ct0hk4
8、说明:更改某个表 G"Pj6QUva
exec sp_changeobjectowner 'tablename','dbo' ^pw7o6}
9、存储更改全部表 =uc^433.
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ha>SZnKD{
@OldOwner as NVARCHAR(128), <9N4"d!A
@NewOwner as NVARCHAR(128) IUawdB5CB
AS =1Sy@M bH3
DECLARE @Name as NVARCHAR(128) MBO,\t.
DECLARE @Owner as NVARCHAR(128) ;tr)=)q&
DECLARE @OwnerName as NVARCHAR(128) Rp4FXR jC
DECLARE curObject CURSOR FOR gMay
select 'Name' = name, npj5U/
'Owner' = user_name(uid) RpeBm#E2
from sysobjects 'FxYMSZS$
where user_name(uid)=@OldOwner BvJ\x)
order by name ^ 0eO\wc?O
OPEN curObject ybYXD?
FETCH NEXT FROM curObject INTO @Name, @Owner j4vB`Gr]
WHILE(@@FETCH_STATUS=0) S)Mby
BEGIN Ij,Yuo
if @Owner=@OldOwner I+~\
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begin 1>;6x^_h0S
set @OwnerName = @OldOwner + '.' + rtrim(@Name) !7Uu]m69n
exec sp_changeobjectowner @OwnerName, @NewOwner eoL0^cZj
end ?\d5;%YSr
-- select @name,@NewOwner,@OldOwner PL!tk^;6-
FETCH NEXT FROM curObject INTO @Name, @Owner J~'~[,K
END S5/p=H:
close curObject Bxt_a.LthH
deallocate curObject un&>
GO dcP88!#5-
10、SQL SERVER中直接循环写入数据 5 iv@@1c
declare @i int )BpIxWd?
set @i=1 vVdxi9yk
while @i<30 _KxX&THaj
begin i8eA_Q
insert into test (userid) values(@i) !|(Ao"]
set @i=@i+1 `W="g6(
end ,i;9[4QMX
小记存储过程中经常用到的本周,本月,本年函数 o[imNy~ ~
Dateadd(wk,datediff(wk,0,getdate()),-1) 4V>vg2
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Dateadd(wk,datediff(wk,0,getdate()),6) K"I{\/x@
Dateadd(mm,datediff(mm,0,getdate()),0) D/*vj|
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) (I!1sE!?1
Dateadd(yy,datediff(yy,0,getdate()),0) F*.
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Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) m]e0X*Kg
上面的SQL代码只是一个时间段 vj(@.uU)
Dateadd(wk,datediff(wk,0,getdate()),-1) sgD@}":m
Dateadd(wk,datediff(wk,0,getdate()),6) hsz$S:am
就是表示本周时间段. x@Sra@
下面的SQL的条件部分,就是查询时间段在本周范围内的: %Au T8
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) nE^wxtY
而在存储过程中 I,w^?o
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) dkETM,
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) i >J:W"W