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。 FqQm*k_
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一、基础 t
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1、说明:创建数据库 'rRo2oTN
CREATE DATABASE database-name rOB-2@-
2、说明:删除数据库 xzy7I6X
drop database dbname ,Vt7Kiu
3、说明:备份sql server ' G-]>
--- 创建 备份数据的 device c}Y(Myd
USE master UMo=bs
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' &6PZX0M
--- 开始 备份 N6$pOQ
BACKUP DATABASE pubs TO testBack oGly|L>
4、说明:创建新表 ,y3o ,gl
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 57)S"
根据已有的表创建新表: s7SW4ff1
A:create table tab_new like tab_old (使用旧表创建新表) 4kNf4l9Y
B:create table tab_new as select col1,col2... from tab_old definition only tk<dp7y7
5、说明:删除新表 ]OM|Oo
drop table tabname 06pLa3oi
6、说明:增加一个列 s9~W( Wi
Alter table tabname add column col type J+[&:]=P
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 b'O>&V`
7、说明:添加主键: Alter table tabname add primary key(col) Gk8"fs
说明:删除主键: Alter table tabname drop primary key(col) z*l3O~mZ
8、说明:创建索引:create [unique] index idxname on tabname(col....) P
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删除索引:drop index idxname A"\kdxC
注:索引是不可更改的,想更改必须删除重新建。 4t|g G`QW7
9、说明:创建视图:create view viewname as select statement Vur$t^zE
删除视图:drop view viewname ,`G8U/
10、说明:几个简单的基本的sql语句 VCcLS3
选择:select * from table1 where 范围 i15uHl
插入:insert into table1(field1,field2) values(value1,value2) 7NMQUN7k'
删除:delete from table1 where 范围 2K!3+D"
更新:update table1 set field1=value1 where 范围 #SQT!4
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! 4s^5t6
排序:select * from table1 order by field1,field2 [desc] -wC;pA#o
总数:select count as totalcount from table1 z6B/H2
求和:select sum(field1) as sumvalue from table1 '[~NRKQJ
平均:select avg(field1) as avgvalue from table1 utQE$0F
最大:select max(field1) as maxvalue from table1 nE+sbfC
最小:select min(field1) as minvalue from table1 *pk*ijdB
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11、说明:几个高级查询运算词 _$NFeqLww
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A: UNION 运算符 C&,&~^_F
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。 :f ybH)*
B: EXCEPT 运算符 KFdV_e5lU
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。 )~T)$TS
C: INTERSECT 运算符 Av^{$9yl
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。
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注:使用运算词的几个查询结果行必须是一致的。 h$DFp
12、说明:使用外连接 J i :2P*
A、left outer join:
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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。 V2,54YE
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 U voX\
B:right outer join: GX&BUP\
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。 =_\5h=`Yx
C:full outer join: n%"q>
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。 >:Na^ +c
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二、提升 'LpJ:Th
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) tlV>
法一:select * into b from a where 1<>1 Q'~kWmLf
法二:select top 0 * into b from a Z%y>q|:
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) e Pq(:ih
insert into b(a, b, c) select d,e,f from b; a57Y9.H`o
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) xM8}Xo
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 fB:9:NX
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. hq6fDRO/4
4、说明:子查询(表名1:a 表名2:b) 1Zx|SBF
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) HlqCL1\<
5、说明:显示文章、提交人和最后回复时间 \-0@9E<D
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b `L`qR,R
6、说明:外连接查询(表名1:a 表名2:b) Ah;2\0|t
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ^G[xQcM73
7、说明:在线视图查询(表名1:a ) -X'HZ\)
select * from (SELECT a,b,c FROM a) T where t.a > 1; bvuoGG*
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 `ky<
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select * from table1 where time between time1 and time2 %2f``48#
select a,b,c, from table1 where a not between 数值1 and 数值2 R5g-b2Lm
9、说明:in 的使用方法 y{,HpPp#o
select * from table1 where a [not] in ('值1','值2','值4','值6') "fdgBso
10、说明:两张关联表,删除主表中已经在副表中没有的信息 A07g@3n
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) --d<s
11、说明:四表联查问题: ;gYW!rM
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 ..... =MEv{9_
12、说明:日程安排提前五分钟提醒 5DK>4H:
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 K}tl,MMU
13、说明:一条sql 语句搞定数据库分页 /1F%w8Iqh
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 %I9{)'+@x
14、说明:前10条记录 X|q&0W=
select top 10 * form table1 where 范围 rIH/<@+
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.) 'C8VD+p
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) "=@b>d6U+
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 n .ZLR=P4
(select a from tableA ) except (select a from tableB) except (select a from tableC) 8i!AJF9IQ}
17、说明:随机取出10条数据 nBI?~hkP3
select top 10 * from tablename order by newid() u =z$**M^
18、说明:随机选择记录 :6S!1roi
select newid() 1 !bODd
19、说明:删除重复记录 Y ( x_bJ
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) U&yXs'3a&
20、说明:列出数据库里所有的表名 .+MJ' bW
select name from sysobjects where type='U' <+o-{{E[
21、说明:列出表里的所有的 jl;_lcO
select name from syscolumns where id=object_id('TableName') rL3<r
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。 mEfI2P)#|
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 ;,[6 n|M
显示结果: z6ISJb
type vender pcs DZ92;m
电脑 A 1 &)JQ6J_|\
电脑 A 1 =.(yOUI
光盘 B 2 >A5R
光盘 A 2 5XySF #
手机 B 3 `E+)e?z
手机 C 3 f uQbDb&
23、说明:初始化表table1 $h`(toTyF
TRUNCATE TABLE table1 !O6e,l
24、说明:选择从10到15的记录 '9c`[^
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc GL[#XB>n
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三、技巧 ZQXv-"
1、1=1,1=2的使用,在SQL语句组合时用的较多 u?5d%]*
"where 1=1" 是表示选择全部 "where 1=2"全部不选, R''nZ/R
如: S-}MS"
if @strWhere !='' fOJ0#^Z
begin %tul(Z~<1
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere [Oen{c9A
end %KHO}gad1
else 8@]*X,umc
begin W^npzgDCo
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' n|2`y?
end Z>gxECi
我们可以直接写成 `bT!_ Ru
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 7 4Xk^8
2、收缩数据库 wI><kdz
--重建索引
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DBCC REINDEX ,@kD9n5#
DBCC INDEXDEFRAG 1^XuH('
--收缩数据和日志 'N^\9X0
DBCC SHRINKDB d0Xb?-
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DBCC SHRINKFILE ^`~M f
3、压缩数据库 _;(`u!@/{
dbcc shrinkdatabase(dbname) ]Q,;5>#W
4、转移数据库给新用户以已存在用户权限 /_<`#?5T(
exec sp_change_users_login 'update_one','newname','oldname' 3[I; 3=O
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5、检查备份集 HeABU(o4
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' !>fYD8Ft,
6、修复数据库 yTzP{I
ALTER DATABASE [dvbbs] SET SINGLE_USER 5v <>%=
GO j[l6&eX
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK x2x)y08
GO JYuI~<:
ALTER DATABASE [dvbbs] SET MULTI_USER E}AOtY5a
GO VeiJ1=hc
7、日志清除 JLUG=x(dA
SET NOCOUNT ON #[0:5$-[
DECLARE @LogicalFileName sysname, ?3X!
@MaxMinutes INT, ddvSi6
@NewSize INT pYZ6-s
USE tablename -- 要操作的数据库名 QR4rQu
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 &7z79#1NS
@MaxMinutes = 10, -- Limit on time allowed to wrap log. U<,@u,_Ja
@NewSize = 1 -- 你想设定的日志文件的大小(M) 2gz}]_
-- Setup / initialize kms&o=^
DECLARE @OriginalSize int D^Ahw"X)
SELECT @OriginalSize = size ,K9\;{C
FROM sysfiles ?&;d#z*4
WHERE name = @LogicalFileName KilgeN:
SELECT 'Original Size of ' + db_name() + ' LOG is ' + CvfXm
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + zvjVM"=G
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 0q'd }D W
FROM sysfiles L[l?}\
WHERE name = @LogicalFileName rMXIw
CREATE TABLE DummyTrans ,:g.B\'Q
(DummyColumn char (8000) not null) r>73IpJI
DECLARE @Counter INT, /~3~Xc~=p
@StartTime DATETIME, (Mi]vK.4
@TruncLog VARCHAR(255) Y.`
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SELECT @StartTime = GETDATE(), Y<|!)JLB2
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' S\fEV"
DBCC SHRINKFILE (@LogicalFileName, @NewSize) 3sG7G:4
EXEC (@TruncLog)
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-- Wrap the log if necessary. Fe
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WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired }L
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AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) /2}o:vLj
AND (@OriginalSize * 8 /1024) > @NewSize 1HQh%dZZ
BEGIN -- Outer loop. ?#8',:
SELECT @Counter = 0 r~cmrLQa
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) #qkokV6`
BEGIN -- update ZeewGa^r
INSERT DummyTrans VALUES ('Fill Log') $YZsaw
DELETE DummyTrans lv
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SELECT @Counter = @Counter + 1 KHwzQ<Z3
END AA][}lU:5
EXEC (@TruncLog) z _qy>
END ~\= VSwJ
SELECT 'Final Size of ' + db_name() + ' LOG is ' + [A$5~/Q{U1
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + &v!=\Fig4
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' LhM{LUi
FROM sysfiles l`lo5:w
WHERE name = @LogicalFileName KrOoxrDcp
DROP TABLE DummyTrans dw
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SET NOCOUNT OFF f[,9WkC
8、说明:更改某个表 %Q]u_0P*
exec sp_changeobjectowner 'tablename','dbo' lfjY45=
9、存储更改全部表 yXU-@~
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch y,qP$5xiq
@OldOwner as NVARCHAR(128), fR_
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@NewOwner as NVARCHAR(128) GwiG..Y]&
AS UeWEncN(
DECLARE @Name as NVARCHAR(128) 1I({2@C
DECLARE @Owner as NVARCHAR(128) G| 7\[!R
DECLARE @OwnerName as NVARCHAR(128) a<X8l^Ln
DECLARE curObject CURSOR FOR blxAy
select 'Name' = name, W{E22J}
'Owner' = user_name(uid) ,#3}TDC
from sysobjects kp3(/`xP
where user_name(uid)=@OldOwner _\E{T5
order by name Gvo(iOU
OPEN curObject @$FE}j_
FETCH NEXT FROM curObject INTO @Name, @Owner (]7*Kq
WHILE(@@FETCH_STATUS=0) 3wXmX
BEGIN >Gbj1>C}
if @Owner=@OldOwner n^|;J*rD
begin lB!`,>"c
set @OwnerName = @OldOwner + '.' + rtrim(@Name) vW4~\]
exec sp_changeobjectowner @OwnerName, @NewOwner -r/G)Rs
end <>aBmJs4
-- select @name,@NewOwner,@OldOwner 5 e:Urv77
FETCH NEXT FROM curObject INTO @Name, @Owner )6|7L)Dk
END `(A6uakd
close curObject /CpUq;^
deallocate curObject 3/IQ]8g"
GO $ tf;\R
10、SQL SERVER中直接循环写入数据 W-wy<<~f
declare @i int g*b
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set @i=1 9 tZ)#@\
while @i<30 9xWC<i
begin %bf+Y7m
insert into test (userid) values(@i) $ q*kD#;mh
set @i=@i+1 -1Y9-nn[m
end gyH'92ck
小记存储过程中经常用到的本周,本月,本年函数 /x.TF'Z*
Dateadd(wk,datediff(wk,0,getdate()),-1) &pwSd
Dateadd(wk,datediff(wk,0,getdate()),6) fr'M)ox1
Dateadd(mm,datediff(mm,0,getdate()),0) ZK5(_qW&i
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) OJE<2:K
Dateadd(yy,datediff(yy,0,getdate()),0)
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Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) HE&,?vioy
上面的SQL代码只是一个时间段 eydVWVN
Dateadd(wk,datediff(wk,0,getdate()),-1) $,08y
Dateadd(wk,datediff(wk,0,getdate()),6)
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就是表示本周时间段. (^GVy=
下面的SQL的条件部分,就是查询时间段在本周范围内的: PpMZ-f@
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 5@c,iU-L
而在存储过程中 /H.QGPr
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) -Hzn7L
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 8)/i\=N3;