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。 *TdnB'Gd
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一、基础 FH5ql~
1、说明:创建数据库 Wsj=!Obc
CREATE DATABASE database-name O9h+Q\0\W
2、说明:删除数据库 GUB`|is^
drop database dbname u' Qd,
3、说明:备份sql server }ynT2a#LU'
--- 创建 备份数据的 device ug&[ IL~lc
USE master Hgc=M
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' 2ef;NC.&n
--- 开始 备份 ~|+zJ5
BACKUP DATABASE pubs TO testBack X=X\F@V:u
4、说明:创建新表 ;GHvPQc_
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) hq>Csj==@
根据已有的表创建新表: &~DTZgY
A:create table tab_new like tab_old (使用旧表创建新表) |FR3w0o
B:create table tab_new as select col1,col2... from tab_old definition only &lc8G
5、说明:删除新表 `m~syKz4A
drop table tabname >um!Eo
6、说明:增加一个列 _O:WG&a6
Alter table tabname add column col type /'DwfX
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。 XAOak$(j
7、说明:添加主键: Alter table tabname add primary key(col) ,t$,idcT+
说明:删除主键: Alter table tabname drop primary key(col) - 0HkT Y
8、说明:创建索引:create [unique] index idxname on tabname(col....) 7YIK9edP
删除索引:drop index idxname ?[)S7\rP
注:索引是不可更改的,想更改必须删除重新建。 ffDc6*.Q
9、说明:创建视图:create view viewname as select statement jk~:\8M(A
删除视图:drop view viewname f`<FT'A
10、说明:几个简单的基本的sql语句 vxlOh.a|/L
选择:select * from table1 where 范围 }k$4/7ri
插入:insert into table1(field1,field2) values(value1,value2) v[k5.\No
删除:delete from table1 where 范围 rjA@U<o
更新:update table1 set field1=value1 where 范围 [pOg'
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! /!FWuRe^
排序:select * from table1 order by field1,field2 [desc] ")#<y@Rv
总数:select count as totalcount from table1 ]hw-Bu\{
求和:select sum(field1) as sumvalue from table1 wNCCH55Pt
平均:select avg(field1) as avgvalue from table1 WV<tyx9Z
最大:select max(field1) as maxvalue from table1 j#A%q"]8
最小:select min(field1) as minvalue from table1 ]5CNk+`'
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11、说明:几个高级查询运算词 QOFvsJ<s
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A: UNION 运算符 |!z2oO
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。 YZ}cB
B: EXCEPT 运算符 - Xupq/[,
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。 &vUq}r%P
C: INTERSECT 运算符 $ACx*e%
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!TZ0fq0
注:使用运算词的几个查询结果行必须是一致的。 Jn}n*t3
12、说明:使用外连接 =C7
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A、left outer join: |WQ9a' '
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。 wGKo.lt
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 mNmUUj9z
B:right outer join: =jAFgwP\
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。 c=p=-j=.J
C:full outer join: s&PM,BFf
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。 E0f{iO;}
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二、提升 u:P~j
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) eQN.sl5
法一:select * into b from a where 1<>1 nS.G~c|
法二:select top 0 * into b from a TR vZ
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) qt?*MyfV
insert into b(a, b, c) select d,e,f from b; kEN#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) >>'C
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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 ETw]!
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例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 8v_C5d\
4、说明:子查询(表名1:a 表名2:b) :-+4:S
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) 0&w0aP`Y
5、说明:显示文章、提交人和最后回复时间 Y*YFB|f?
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b laREjN/\`
6、说明:外连接查询(表名1:a 表名2:b) Opg#*w%-
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 4iX-( ir,
7、说明:在线视图查询(表名1:a ) +&v\
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select * from (SELECT a,b,c FROM a) T where t.a > 1; ~UMOT!4}3
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 VV3}]GjC
select * from table1 where time between time1 and time2 S3\jcgrS
select a,b,c, from table1 where a not between 数值1 and 数值2 5D`26dB2
9、说明:in 的使用方法 e<+<lj"
select * from table1 where a [not] in ('值1','值2','值4','值6') Lk,+Tfk"
10、说明:两张关联表,删除主表中已经在副表中没有的信息 n'w,n1z7
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) FvImX
11、说明:四表联查问题: gQVBA %
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 ..... hl/itSl$
12、说明:日程安排提前五分钟提醒 3(_!`0#F%
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 bH9Le
13、说明:一条sql 语句搞定数据库分页 POd/+e9d
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 \_ow9vU
14、说明:前10条记录 vgG}d8MW37
select top 10 * form table1 where 范围 :F(9"L
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.) mUXk9X%n
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) ohZx03
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 &d^=siL
(select a from tableA ) except (select a from tableB) except (select a from tableC) &a #GXf
17、说明:随机取出10条数据 S`g;Y
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select top 10 * from tablename order by newid() 3:`XG2'
18、说明:随机选择记录 f\o
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select newid() Os&1..$Nb
19、说明:删除重复记录 ;;#nV$
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) Jq1 n0O
20、说明:列出数据库里所有的表名 c ~Kc7}I
select name from sysobjects where type='U' $G";2(-k
21、说明:列出表里的所有的 8F6h#%9
select name from syscolumns where id=object_id('TableName') WmVVR>0V|
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 ejcwg*i
select type,sum(case vender when 'A' then pcs else 0 end),sum(case vender when 'C' then pcs else 0 end),sum(case vender when 'B' then pcs else 0 end) FROM tablename group by type f_<Y\
显示结果: SGf9U^ds
type vender pcs 6Z c)0I'
电脑 A 1 %$n02"@
电脑 A 1 Bymny>.M
光盘 B 2 $WaZ_kt
光盘 A 2 +VOb
手机 B 3 gxM[V>[
手机 C 3 [thboP.?
23、说明:初始化表table1 +TX/g~
TRUNCATE TABLE table1 y^s1t2]%
24、说明:选择从10到15的记录 i^/54
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc <94WZ?{p
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三、技巧 K-@bwB7~s
1、1=1,1=2的使用,在SQL语句组合时用的较多 ~3 @*7B5Q
"where 1=1" 是表示选择全部 "where 1=2"全部不选,
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如: 2Ow<`[7
if @strWhere !=''
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begin w%u5<
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere WOb8"*OM
end `o-*Tr
else {3 o%d:
begin <7RfBR.9
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' NbDda/7ki
end h AAU ecx
我们可以直接写成 VM;g+RRq
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere :uvc\|:s
2、收缩数据库 04\Ta
--重建索引 IUawdB5CB
DBCC REINDEX Fwv\ pJ}$
DBCC INDEXDEFRAG +$~8)95<B
--收缩数据和日志 )@$
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DBCC SHRINKDB 1.dX)^\
DBCC SHRINKFILE 'FxYMSZS$
3、压缩数据库 ULu O0\W
dbcc shrinkdatabase(dbname) f?m5pax|
4、转移数据库给新用户以已存在用户权限 3N3*`?5c<
exec sp_change_users_login 'update_one','newname','oldname' hg&u0AQ2
go $QffrU'
5、检查备份集 T>5wQYh$'
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' )|:8zDuJ
6、修复数据库 `D"1
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ALTER DATABASE [dvbbs] SET SINGLE_USER /J.0s0@
GO ]:!8 s\#
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK At|ht
GO cf&C|U
ALTER DATABASE [dvbbs] SET MULTI_USER 2;}xN! 8
GO _KxX&THaj
7、日志清除 -s33m]a;
SET NOCOUNT ON V^WQ6G1
DECLARE @LogicalFileName sysname, m&ZJqsZIL
@MaxMinutes INT, vcV!K^M-
@NewSize INT F]0Jwm{
USE tablename -- 要操作的数据库名 P;>!wU~*
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 /O_0=MLp
@MaxMinutes = 10, -- Limit on time allowed to wrap log. d}pGeU'
@NewSize = 1 -- 你想设定的日志文件的大小(M) 3U>S]#5}
-- Setup / initialize WQTendS
DECLARE @OriginalSize int % dYI5U89
SELECT @OriginalSize = size eoC<a"bJ>
FROM sysfiles wNbTM.@
WHERE name = @LogicalFileName sq48#5Tc^r
SELECT 'Original Size of ' + db_name() + ' LOG is ' + qjzZ}
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + WEps.]s
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' 7Z
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FROM sysfiles ~V!EtZG$
WHERE name = @LogicalFileName C\J@fpH(t`
CREATE TABLE DummyTrans . ^BWR
(DummyColumn char (8000) not null) 83B\+]{hD
DECLARE @Counter INT, $=7H1 w
@StartTime DATETIME, #% qqL
@TruncLog VARCHAR(255) Fu#Y7)r
SELECT @StartTime = GETDATE(), F61+n!%8
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' 1XQ87~
DBCC SHRINKFILE (@LogicalFileName, @NewSize) +7`u9j.
EXEC (@TruncLog) *P&OxVz
-- Wrap the log if necessary. |%n|[LP'
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired N4'
.a=1
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) LxIuxt=X|p
AND (@OriginalSize * 8 /1024) > @NewSize d"z *Nb
BEGIN -- Outer loop. W&Y4Dq^
SELECT @Counter = 0 ZV0)
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WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) _Wq7U1v`
BEGIN -- update fQ^h{n
INSERT DummyTrans VALUES ('Fill Log') )x y9X0
DELETE DummyTrans X5|?/aR}
SELECT @Counter = @Counter + 1 \%Pma8&d
END x/pC%25
EXEC (@TruncLog) W=q?tD~V
END Mf!owpW
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + G1,Ro1
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + :Xb*m85y
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' %
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FROM sysfiles (M4]#5
WHERE name = @LogicalFileName 4&#vU(-H
DROP TABLE DummyTrans $XU-[OF%:9
SET NOCOUNT OFF 0^-z?Kb<}
8、说明:更改某个表 FI80vV7
exec sp_changeobjectowner 'tablename','dbo' <t% Ao,"
9、存储更改全部表 AEBw#v!,o
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch t201ud2$
@OldOwner as NVARCHAR(128), "-G.V#zI
@NewOwner as NVARCHAR(128) fJ,8g/f8
AS J+-,^8)
DECLARE @Name as NVARCHAR(128) ZS07_6.~
DECLARE @Owner as NVARCHAR(128) O%rS;o
DECLARE @OwnerName as NVARCHAR(128) 0tn7Rkiw
DECLARE curObject CURSOR FOR 0b!fWS?,k0
select 'Name' = name, &Z#Vw.7U
'Owner' = user_name(uid) ":5~L9&G
from sysobjects QSlf=VK*y
where user_name(uid)=@OldOwner Z3&XTsq
order by name Zb5T90s%
OPEN curObject 3/]f4D{MMY
FETCH NEXT FROM curObject INTO @Name, @Owner Py( w T%w
WHILE(@@FETCH_STATUS=0) 0nF>zOmc
BEGIN Iwd"f
if @Owner=@OldOwner &@Ji+
begin F!DrZd>\
set @OwnerName = @OldOwner + '.' + rtrim(@Name) FuRn%)DA5
exec sp_changeobjectowner @OwnerName, @NewOwner J-HabHv
end wFH(.E0@Q
-- select @name,@NewOwner,@OldOwner B)LXxdkOn
FETCH NEXT FROM curObject INTO @Name, @Owner -M(58/y
END _A# x&<c
close curObject "' LOaf$X
deallocate curObject C 6:p Y-
GO
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10、SQL SERVER中直接循环写入数据 IWSEssP
declare @i int +#2@G}j
set @i=1 c{r6a=C
while @i<30 vM$#m1L?
begin J[Y lo&w3
insert into test (userid) values(@i) O>{t}6o
set @i=@i+1 W"DxIy
end 7i%P&oB
小记存储过程中经常用到的本周,本月,本年函数 P-*RN
Dateadd(wk,datediff(wk,0,getdate()),-1) TO8\4p*tE
Dateadd(wk,datediff(wk,0,getdate()),6) !7#froh
Dateadd(mm,datediff(mm,0,getdate()),0) /-cX(z
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Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) yM\tbT/l
Dateadd(yy,datediff(yy,0,getdate()),0) KH CdO
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) UBpM8 /U
上面的SQL代码只是一个时间段 _@}MGWlAPt
Dateadd(wk,datediff(wk,0,getdate()),-1) a|^-z|.
Dateadd(wk,datediff(wk,0,getdate()),6) aF_ZV bS
就是表示本周时间段. cUX]tiC0
下面的SQL的条件部分,就是查询时间段在本周范围内的: _a:!U^4
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) zke~!"iq
而在存储过程中 D6@4
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) oBGst t@
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) A+Pm "|