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。 AGK{t+`
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一、基础 `[F[0fY-
1、说明:创建数据库 ^|ul3_'?
CREATE DATABASE database-name !MEA@^$#
2、说明:删除数据库 V* H7m'za
drop database dbname (Z?g^kjq)
3、说明:备份sql server SshjUNx
--- 创建 备份数据的 device @f`s%o
USE master WuMr";2*E
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' KZ$^Q<d^
--- 开始 备份 Z=zD~ka
BACKUP DATABASE pubs TO testBack UqNUP+K
4、说明:创建新表 ; ~#uH7k
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) g^[BnP)I
根据已有的表创建新表: v?s%qb= T
A:create table tab_new like tab_old (使用旧表创建新表) _l=X?/
B:create table tab_new as select col1,col2... from tab_old definition only ]^I[SG,
5、说明:删除新表 nJcY>Rp?
drop table tabname sDP8!
6、说明:增加一个列 j6#Vwc r
Alter table tabname add column col type 'pC51}[A{^
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。 Oj#/R?%,X
7、说明:添加主键: Alter table tabname add primary key(col) /TY=ig1z
说明:删除主键: Alter table tabname drop primary key(col) M s Q=1
8、说明:创建索引:create [unique] index idxname on tabname(col....) g<^-[w4/
删除索引:drop index idxname Y}
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注:索引是不可更改的,想更改必须删除重新建。 \
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9、说明:创建视图:create view viewname as select statement e,Sxu[2
删除视图:drop view viewname U[|o!2$
10、说明:几个简单的基本的sql语句 8XD_p);Oy
选择:select * from table1 where 范围 !+_X q$9_
插入:insert into table1(field1,field2) values(value1,value2)
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删除:delete from table1 where 范围 cS RmC
更新:update table1 set field1=value1 where 范围 lt& c/xi_
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! `2,F!kCt
排序:select * from table1 order by field1,field2 [desc] ,L-G-V+
总数:select count as totalcount from table1 csj4?]gI
求和:select sum(field1) as sumvalue from table1 )}1S
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平均:select avg(field1) as avgvalue from table1 b_']S0$c\
最大:select max(field1) as maxvalue from table1 `ZGKM>q`
最小:select min(field1) as minvalue from table1 T[%@B"
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11、说明:几个高级查询运算词 Lrq e:\
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A: UNION 运算符 q+W*?a)
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。 U(5 Yg
B: EXCEPT 运算符 4q*mEV
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。 I\@`AU
C: INTERSECT 运算符 {QVs[
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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。
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注:使用运算词的几个查询结果行必须是一致的。 ASUleOI79(
12、说明:使用外连接 EM!9_8 f
A、left outer join: >r.W \
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。 2<tU
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 cBQ+`DXn5c
B:right outer join: \-CL}Z}S
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。 H0-v^H>^
C:full outer join: La
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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。 SHRn$<
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二、提升 g[(Eh?]Sc
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) z4 KKt&
法一:select * into b from a where 1<>1 rkn'1M&u
法二:select top 0 * into b from a ]K|td)1X
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) :(#5%6F
insert into b(a, b, c) select d,e,f from b; B}^l'p_u
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) kHd`k.nW
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 :5_394v
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 'M,O(utGv
4、说明:子查询(表名1:a 表名2:b) o_n 3.O=
select a,b,c from a where a IN (select d from b ) 或者: select a,b,c from a where a IN (1,2,3) dWiX_&g
5、说明:显示文章、提交人和最后回复时间 oW3|b2D
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b m-lTXA(
6、说明:外连接查询(表名1:a 表名2:b) DVjwY_nG7
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 1@xdzKua1
7、说明:在线视图查询(表名1:a ) 3u[5T|D'
select * from (SELECT a,b,c FROM a) T where t.a > 1; W|\$}@>
8、说明:between的用法,between限制查询数据范围时包括了边界值,not between不包括 Ca
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select * from table1 where time between time1 and time2 v$#l]A_D
select a,b,c, from table1 where a not between 数值1 and 数值2 T9bUt |
9、说明:in 的使用方法 lsKQZ@LN`
select * from table1 where a [not] in ('值1','值2','值4','值6') i!yE#zew
10、说明:两张关联表,删除主表中已经在副表中没有的信息 G$VE
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delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) sf8F h
11、说明:四表联查问题: 6Cgc-KNbk
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... .q|k459oi
12、说明:日程安排提前五分钟提醒 P.-
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SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 (: @7IWZf@
13、说明:一条sql 语句搞定数据库分页 ftD(ed
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 "~L$oji
14、说明:前10条记录 dz1kQzOU*
select top 10 * form table1 where 范围 >1 hhz
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.) Wv]ODEd
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) </D )i
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 6UM1>xq9A
(select a from tableA ) except (select a from tableB) except (select a from tableC) wicW9^ik
17、说明:随机取出10条数据 dZCnQ IS
select top 10 * from tablename order by newid() v(=E R%
18、说明:随机选择记录 $8`"
select newid() SE6c3
19、说明:删除重复记录 7KN+ @6!x
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) ^/~C\
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20、说明:列出数据库里所有的表名 &/(JIWc1su
select name from sysobjects where type='U' X<&Y5\%F
21、说明:列出表里的所有的 3,1HD_
select name from syscolumns where id=object_id('TableName') r0q?e`nsA
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 JC
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select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type fndbGbl8p
显示结果: RaOLy \
type vender pcs Y|E rVf4
电脑 A 1 wY"BPl]b
电脑 A 1 #'BPW<Ob
光盘 B 2 8wMwS6s:
光盘 A 2 <YvW /x
手机 B 3 BT"n;L?[
手机 C 3 .yB{+
23、说明:初始化表table1 RcOfesW
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TRUNCATE TABLE table1 #U.6HBuQa
24、说明:选择从10到15的记录 ?X$*8;==6
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc [F
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三、技巧 ydMSL25<+
1、1=1,1=2的使用,在SQL语句组合时用的较多 U04&z 91"
"where 1=1" 是表示选择全部 "where 1=2"全部不选, W0<2*7s
如: 1NkJs&
if @strWhere !='' dUv(Pu(.#
begin 6pbtE]
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere $E}N`B7
end \LM.>vJ
else LIn2&r:U
begin A45!hhf
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' k|^`0~E
end qWD(rq+9
我们可以直接写成 O bc>f|l]
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere u}89v1._Jn
2、收缩数据库 b-Ru UfUn0
--重建索引 m .R**g
DBCC REINDEX f$qkb$?]}
DBCC INDEXDEFRAG }6gum
--收缩数据和日志 s7,D}Zz
DBCC SHRINKDB 1rON8=E
DBCC SHRINKFILE rTqGtmulG
3、压缩数据库 &r2\P6J
dbcc shrinkdatabase(dbname) 73JrK_h
4、转移数据库给新用户以已存在用户权限 )FN$Jlo
exec sp_change_users_login 'update_one','newname','oldname' E6zPN?\ <
go F>eo.|'
5、检查备份集 9 dK`
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' S|F:[(WaM
6、修复数据库 6zI}?KZf
ALTER DATABASE [dvbbs] SET SINGLE_USER lN x7$z`
GO vsJDVJ +=
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK <`WcI`IAb
GO )r?-_qj=
ALTER DATABASE [dvbbs] SET MULTI_USER sgRWjrc/
GO a%5/Oc[[
7、日志清除 <6+T&Ov6
SET NOCOUNT ON 7"1]5\p^g
DECLARE @LogicalFileName sysname, $g),|[x+(
@MaxMinutes INT, \2CEEs'
@NewSize INT Yr[&*>S
USE tablename -- 要操作的数据库名 J?Oeuk~[D
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 3i~X`@$k>
@MaxMinutes = 10, -- Limit on time allowed to wrap log. L3A2A
@NewSize = 1 -- 你想设定的日志文件的大小(M) 'mZQ}U=<
-- Setup / initialize )iFXa<5h
DECLARE @OriginalSize int }G<~Cx5[
SELECT @OriginalSize = size rU6A^p\,
FROM sysfiles FIUQQQ\3
WHERE name = @LogicalFileName / }*}r
SELECT 'Original Size of ' + db_name() + ' LOG is ' + u:^sEk"Lk'
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + <GF^VT|Ce
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' !t}yoN
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FROM sysfiles BN~ndWRK
WHERE name = @LogicalFileName RFX{]bQp9
CREATE TABLE DummyTrans !(gSXe)*
(DummyColumn char (8000) not null) =.w~qL
DECLARE @Counter INT, $hMD6<e
@StartTime DATETIME, MBAj.J
@TruncLog VARCHAR(255) Qe-PW9C
SELECT @StartTime = GETDATE(), <W+9h0c
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' AH_qZTv0{Q
DBCC SHRINKFILE (@LogicalFileName, @NewSize) "BZ@m:I6hy
EXEC (@TruncLog) 3O;"{E=
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-- Wrap the log if necessary. }Rw6+;
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired ).AMfBQ=;
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) "Q{l])N
AND (@OriginalSize * 8 /1024) > @NewSize | AiMx2
BEGIN -- Outer loop.
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SELECT @Counter = 0 0T^0)c
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) )?pnV":2Y
BEGIN -- update )j\_*SoH
INSERT DummyTrans VALUES ('Fill Log') q@tym5
DELETE DummyTrans _07$TC1
SELECT @Counter = @Counter + 1 =3!o_
END p$uPj*
EXEC (@TruncLog) *f_A:`:
END
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + VJ?>o
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + XUnw*3tPJ
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' T#wG]DH;
FROM sysfiles Cc;8+Z=a?G
WHERE name = @LogicalFileName vPc*x5w-
DROP TABLE DummyTrans $HtGB]
SET NOCOUNT OFF "YWZ&_n**
8、说明:更改某个表 Ay PtbrO
exec sp_changeobjectowner 'tablename','dbo' H \'1.8g/
9、存储更改全部表 ZCViZWo
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 64]8ykRD-
@OldOwner as NVARCHAR(128), @BG].UJo
@NewOwner as NVARCHAR(128) `WnsM;1Y"
AS dFA1nn6{
DECLARE @Name as NVARCHAR(128) uB#U(
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DECLARE @Owner as NVARCHAR(128) [ D.%v~j
DECLARE @OwnerName as NVARCHAR(128) C!ch
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DECLARE curObject CURSOR FOR k/sfak{Q
select 'Name' = name, LNyrIk/1
'Owner' = user_name(uid) +k~0&lZi
from sysobjects %M))Ak4~a
where user_name(uid)=@OldOwner (w:,iw#
order by name >239SyC-,
OPEN curObject boHbiE
FETCH NEXT FROM curObject INTO @Name, @Owner fx>U2
WHILE(@@FETCH_STATUS=0) oOC&w0
BEGIN x/wgD'?
if @Owner=@OldOwner _ Yc"{d3S
begin 3zu6#3^
set @OwnerName = @OldOwner + '.' + rtrim(@Name) *ra>Kl0
exec sp_changeobjectowner @OwnerName, @NewOwner Ga-cto1Y
end cpALs1j:
-- select @name,@NewOwner,@OldOwner LrT EF
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FETCH NEXT FROM curObject INTO @Name, @Owner \P")Eh =d
END V)l:fUm2
close curObject [`s0 L#
deallocate curObject j--byk6PB
GO a(=lQ(v/?
10、SQL SERVER中直接循环写入数据 @0]WMI9B"B
declare @i int -
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set @i=1 ?$T ^L"~
while @i<30 w52py7
begin l#%7BGwzY
insert into test (userid) values(@i) 'O\ y7"a
set @i=@i+1 "qd|!:bE
end gPb.%^p
小记存储过程中经常用到的本周,本月,本年函数 >3@3~F%xAX
Dateadd(wk,datediff(wk,0,getdate()),-1) jT}={[9b
Dateadd(wk,datediff(wk,0,getdate()),6) MtaGv#mJ
Dateadd(mm,datediff(mm,0,getdate()),0) ^m&I^ \
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) y j#*H
Dateadd(yy,datediff(yy,0,getdate()),0) 3ce$eZE
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) =QGmJ3
上面的SQL代码只是一个时间段 Ff(};$/&W
Dateadd(wk,datediff(wk,0,getdate()),-1) NkO+)=
Dateadd(wk,datediff(wk,0,getdate()),6) DBL@Mp[<
就是表示本周时间段. GqR|hg
下面的SQL的条件部分,就是查询时间段在本周范围内的: o-7{\%+M
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) yNowhh
而在存储过程中 Z"%.
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) ?|+e*{4k
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 2[HPU M2>