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.SDM z
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一、基础 | \AbL!u
1、说明:创建数据库 7J0 ^N7"o
CREATE DATABASE database-name !8wZw68"
2、说明:删除数据库 +A'}PXm*tu
drop database dbname v>JB
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3、说明:备份sql server 'u4}t5Bu5
--- 创建 备份数据的 device ;X+G6F'
USE master bq c;.4$
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' h{Oz*Bq
--- 开始 备份 Sja"(sJ
BACKUP DATABASE pubs TO testBack U,oD44
4、说明:创建新表 4aj[5fhb-
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) t9-_a5>E\}
根据已有的表创建新表: '}wG"0
A:create table tab_new like tab_old (使用旧表创建新表) O4lxeiRgC
B:create table tab_new as select col1,col2... from tab_old definition only )fxo)GS
5、说明:删除新表 1i5 vW- '4
drop table tabname D
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6、说明:增加一个列 5Z^$`$/.v#
Alter table tabname add column col type 6&g!ZE'G
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。 38"8,k
7、说明:添加主键: Alter table tabname add primary key(col) O{;M6U8C\
说明:删除主键: Alter table tabname drop primary key(col) e7Yb=/F
8、说明:创建索引:create [unique] index idxname on tabname(col....) M\:"~XW
删除索引:drop index idxname ?whRlh
注:索引是不可更改的,想更改必须删除重新建。 3c1o,2
9、说明:创建视图:create view viewname as select statement 2z.k)Qx!Z
删除视图:drop view viewname ^AovkK(p
10、说明:几个简单的基本的sql语句 0lLr[
选择:select * from table1 where 范围 Wwn5LlJ^
插入:insert into table1(field1,field2) values(value1,value2) P Xyyyir{
删除:delete from table1 where 范围 ?9o#%?6k
更新:update table1 set field1=value1 where 范围 2&^,IIp
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! $ka1X&f
排序:select * from table1 order by field1,field2 [desc] +W V@o'
总数:select count as totalcount from table1 Iu=pk@*O
求和:select sum(field1) as sumvalue from table1 nG&w0de<>
平均:select avg(field1) as avgvalue from table1 D]t~S1ycG7
最大:select max(field1) as maxvalue from table1 h1Ke$#$6
最小:select min(field1) as minvalue from table1 sq8 tv]
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11、说明:几个高级查询运算词 OGSEvfW
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A: UNION 运算符 Pur"9jHa4
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。 Hl%+F0^?
B: EXCEPT 运算符 -L^0-g
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。 Mft0Dj/
C: INTERSECT 运算符 9`nP(~
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。 *X-~TC0
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注:使用运算词的几个查询结果行必须是一致的。 i~v@
12、说明:使用外连接 [8V(N2
A、left outer join: TE*> a5C|
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。 #Pe\Z/
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 kphy7>Km
B:right outer join: zJB+C=]D7H
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。 ,g<>`={kK+
C:full outer join: :kf3_?9rc
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。 [# H8=
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二、提升 pAPQi|CN
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) !5g)3St
法一:select * into b from a where 1<>1 4wM$5
法二:select top 0 * into b from a sT;=7L<TA
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) D{&+7C:8.
insert into b(a, b, c) select d,e,f from b; PuUon6bZ
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) D7Rbho<
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 a$+e8>
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. a9mr-`<
4、说明:子查询(表名1:a 表名2:b) T }8r;<P6
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) p ] $
5、说明:显示文章、提交人和最后回复时间 W#JVU GYD
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b '|dKg"Yl
6、说明:外连接查询(表名1:a 表名2:b) &9jUf:g J0
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c +e{djp@m
7、说明:在线视图查询(表名1:a ) ;GSfN
select * from (SELECT a,b,c FROM a) T where t.a > 1; :5q*46n
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 P /f ~
select * from table1 where time between time1 and time2 h!JjN$
select a,b,c, from table1 where a not between 数值1 and 数值2 E|8s2t
9、说明:in 的使用方法 I'6ed`|
select * from table1 where a [not] in ('值1','值2','值4','值6') \nWzn4f
10、说明:两张关联表,删除主表中已经在副表中没有的信息 hg86#jq%
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) |Ls&~'ik
11、说明:四表联查问题: 8WLh]MD`
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 ..... ^<5^9]x
12、说明:日程安排提前五分钟提醒 '3Lx!pMhN
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 %n V@'3EI
13、说明:一条sql 语句搞定数据库分页 ( .6tz
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 R- ?0k:
14、说明:前10条记录 a3E*%G
select top 10 * form table1 where 范围 |)>GeE
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.) ><Mbea=U+
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) q4IjCu+
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 `OF;>u*:
(select a from tableA ) except (select a from tableB) except (select a from tableC) BZ'y}Zu*
17、说明:随机取出10条数据 #L+s%OJ`
select top 10 * from tablename order by newid() se*pkgWbz
18、说明:随机选择记录 'Rar>oU
select newid() H'0J1\ h
19、说明:删除重复记录 9g^./k\8%
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) {F{[!.
20、说明:列出数据库里所有的表名 .Q6{$Y%l
select name from sysobjects where type='U' =f{Z~`3
21、说明:列出表里的所有的 ,_X,V!
select name from syscolumns where id=object_id('TableName') YM,D`c[pX
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 b}q(YgH<
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type @v:ILby4-
显示结果: 5kL# V
type vender pcs 0UAr}H.:
电脑 A 1 :XZJx gx
电脑 A 1 /[)P^L`
光盘 B 2 (}7o
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光盘 A 2 4j=@}!TBt
手机 B 3 fPuQ,J2=
手机 C 3 oqm{<g?2
23、说明:初始化表table1 V[2<ha[n>
TRUNCATE TABLE table1 14)kKWG
24、说明:选择从10到15的记录 <pa];k(IQL
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc *^$N$t/2
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三、技巧 !nD[hI8P
1、1=1,1=2的使用,在SQL语句组合时用的较多 IEKX'+t'
"where 1=1" 是表示选择全部 "where 1=2"全部不选, Z#E#P<&d
如: TlZlE^EE<
if @strWhere !='' >!ZyykAs
begin 0a;FX0S&
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere Jut'xA2Dr
end 0z2R`=)
else E4fvYV_ra
begin vXWESy
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' Dqo:X`<bT
end 9?mOLDu}Q0
我们可以直接写成 S
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set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere ^O\1v
2、收缩数据库 w}KcLaI
--重建索引 &wWGZ~T
DBCC REINDEX I>(z)"1
DBCC INDEXDEFRAG b*%WAVt2T
--收缩数据和日志 iF2IR{h
DBCC SHRINKDB dIh(~KqB
DBCC SHRINKFILE #JT%]!
3、压缩数据库 UqQZ
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dbcc shrinkdatabase(dbname) (h(ZL9!
4、转移数据库给新用户以已存在用户权限 q|Tk+JH{5
exec sp_change_users_login 'update_one','newname','oldname' TbUkqABm
go S>zKD
5、检查备份集 jC }u>AB
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' ieg PEb
6、修复数据库 ^ZZ@!Udy
ALTER DATABASE [dvbbs] SET SINGLE_USER C3`.-/{D"
GO K`mxb}
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK !"qEB2r
GO gM/_:+bT>P
ALTER DATABASE [dvbbs] SET MULTI_USER BqJrL/(
GO zqEZ+|c=
7、日志清除 !c;p4B)
SET NOCOUNT ON {>qrf:
DECLARE @LogicalFileName sysname, K^p"Z$$
@MaxMinutes INT, !i lDR<
@NewSize INT \$++.%0
USE tablename -- 要操作的数据库名 _rWXcK3cjr
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 tbt9V2U:"n
@MaxMinutes = 10, -- Limit on time allowed to wrap log. 63\>MQcLy
@NewSize = 1 -- 你想设定的日志文件的大小(M) ,kuFTWB
-- Setup / initialize ="*C&wB^
DECLARE @OriginalSize int cyn]>1ZM
SELECT @OriginalSize = size >L3p qK
FROM sysfiles &5CeRx7%
WHERE name = @LogicalFileName uqH! eN5
SELECT 'Original Size of ' + db_name() + ' LOG is ' + {:!SH6 ff
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + bJu,R-f
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' TuPxyB
FROM sysfiles u(Q(UuI
WHERE name = @LogicalFileName _!T$|,a
CREATE TABLE DummyTrans p5 PON0dS
(DummyColumn char (8000) not null) Z-=7QK.\{
DECLARE @Counter INT, &]A1 _dy
@StartTime DATETIME, ~wV98u-N
@TruncLog VARCHAR(255) o`]FH_
SELECT @StartTime = GETDATE(), +Gs;3jC^
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' m^&mCo,
DBCC SHRINKFILE (@LogicalFileName, @NewSize) *^m.V=
EXEC (@TruncLog) Gf$>!zXr
-- Wrap the log if necessary. ojI"<Q~g
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired v*p)"J *
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) Nr7.BDA
AND (@OriginalSize * 8 /1024) > @NewSize l`G:@}P>G
BEGIN -- Outer loop. -x5bdC(d
SELECT @Counter = 0 ;:YjgZ:+Q]
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) T{kwy3
BEGIN -- update D%}o26K.C
INSERT DummyTrans VALUES ('Fill Log') $BN+SD!
DELETE DummyTrans (9QRg;
SELECT @Counter = @Counter + 1 ~w%+y
END v\T1,Z@N^
EXEC (@TruncLog) \YyU5f7';
END %=>xzP(z
SELECT 'Final Size of ' + db_name() + ' LOG is ' + 2{qG
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + YS6az0ie
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' MA QY/s~F
FROM sysfiles 2]KPW*V
WHERE name = @LogicalFileName :D7!6}%
DROP TABLE DummyTrans DO*C]
SET NOCOUNT OFF Icb;Yzt
8、说明:更改某个表 v2<gkCK^
exec sp_changeobjectowner 'tablename','dbo' IWd*"\L
9、存储更改全部表 %&S]cEw
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch 0|k[Wha#
@OldOwner as NVARCHAR(128), /9gMcn9EB
@NewOwner as NVARCHAR(128) %}MM+1eu
AS I!@`_Q9N
DECLARE @Name as NVARCHAR(128) DEuW' .o>
DECLARE @Owner as NVARCHAR(128) !KW)*
DECLARE @OwnerName as NVARCHAR(128) z{_Vn(Kg
DECLARE curObject CURSOR FOR T+( A7Qrx%
select 'Name' = name, En%o7^W++
'Owner' = user_name(uid) OF}_RGKg3
from sysobjects TW?
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where user_name(uid)=@OldOwner )W3l{T(
order by name a];i4lt(c
OPEN curObject ,RH986,6V
FETCH NEXT FROM curObject INTO @Name, @Owner 7i\[Q8f
WHILE(@@FETCH_STATUS=0) 5Wjp_^!e
BEGIN :O=Vr]Y8K
if @Owner=@OldOwner &~i
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begin f2XD^:Gc
set @OwnerName = @OldOwner + '.' + rtrim(@Name) e;\c=J,eE
exec sp_changeobjectowner @OwnerName, @NewOwner Wx`IEPsVbk
end S'fq/`2g6
-- select @name,@NewOwner,@OldOwner ?Cl"jcQ*
FETCH NEXT FROM curObject INTO @Name, @Owner D~);:}}>
END "Vy\- ^
close curObject P_%l}%
deallocate curObject ~Dh}E9E:
GO |EA1+I.&x
10、SQL SERVER中直接循环写入数据 %ua5T9H Z
declare @i int $^GnY7$!>
set @i=1 8`<GplO
while @i<30 :RG6gvz
begin q|\Cp
insert into test (userid) values(@i) VUhu"h@w%
set @i=@i+1 2sq<"TlQXI
end C*zdHzMj
小记存储过程中经常用到的本周,本月,本年函数 s_Gp +-
Dateadd(wk,datediff(wk,0,getdate()),-1) 6YbSzx`?k
Dateadd(wk,datediff(wk,0,getdate()),6) I>|?B(F
Dateadd(mm,datediff(mm,0,getdate()),0) j(N9%/4u
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) 81C?U5
Dateadd(yy,datediff(yy,0,getdate()),0) (CwaOm{g
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) SJe;T
上面的SQL代码只是一个时间段 Nzt1JHRS
Dateadd(wk,datediff(wk,0,getdate()),-1) SesO$=y
Dateadd(wk,datediff(wk,0,getdate()),6) bBL"F!.
就是表示本周时间段. }3e+D
下面的SQL的条件部分,就是查询时间段在本周范围内的: \6L=^q=
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) P40eK0e6
而在存储过程中 S d -+a
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) *8+YR
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) ru
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