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。 .L7Yf+yFg
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一、基础 LR3`=Z9
1、说明:创建数据库 5U{4TeUH
CREATE DATABASE database-name }B"|z'u
2、说明:删除数据库 =1*%>K
drop database dbname Kr/h`RM
3、说明:备份sql server ?Z Rkn+;
--- 创建 备份数据的 device OyJsz]b} M
USE master t0e{|du
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' (@ fa~?v>@
--- 开始 备份 y98JiNq
BACKUP DATABASE pubs TO testBack 3zB|!pC6s
4、说明:创建新表 DhLr^Z!h3;
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) 1Sg|3T8bGT
根据已有的表创建新表: 3+(yI 4
A:create table tab_new like tab_old (使用旧表创建新表) }A1|jY)x
B:create table tab_new as select col1,col2... from tab_old definition only u3Usq=Ij{
5、说明:删除新表 }UKgF.
drop table tabname 4<T*i{[
6、说明:增加一个列 0{?:FQ#
Alter table tabname add column col type C5es2!^-]O
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;z;vrrL
7、说明:添加主键: Alter table tabname add primary key(col) e^k!vk-SLF
说明:删除主键: Alter table tabname drop primary key(col) _BG8/"h32
8、说明:创建索引:create [unique] index idxname on tabname(col....) 7q%|4Z-~
删除索引:drop index idxname 5zNSEI"PY
注:索引是不可更改的,想更改必须删除重新建。 EqD^/(,L2
9、说明:创建视图:create view viewname as select statement `]`=]*d
删除视图:drop view viewname 7
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10、说明:几个简单的基本的sql语句 *A?8F"6>
选择:select * from table1 where 范围 %cH8;5U40
插入:insert into table1(field1,field2) values(value1,value2) >vWEUE[
删除:delete from table1 where 范围 +
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更新:update table1 set field1=value1 where 范围 _urG_~q
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! oL<BLr9>
排序:select * from table1 order by field1,field2 [desc] "jL1.9%"
总数:select count as totalcount from table1 }#yU'#|d
求和:select sum(field1) as sumvalue from table1 Dv<wge`
平均:select avg(field1) as avgvalue from table1 )|y#OZHR
最大:select max(field1) as maxvalue from table1 Hf VHI1f
最小:select min(field1) as minvalue from table1 wgY6D!Y
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11、说明:几个高级查询运算词 .#*D!;f
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A: UNION 运算符 !*&4< _
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。 JC=dYP}
B: EXCEPT 运算符 sffhPX\I
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。 D =$4/D:;
C: INTERSECT 运算符 9khjwt
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 'gCJ[ ce
注:使用运算词的几个查询结果行必须是一致的。 cZqfz
12、说明:使用外连接 3 m6$YWO
A、left outer join: mge#YV::
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。 ]k[x9,IU\y
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
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B:right outer join: FJ{=2]x|
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.E[6G3
C:full outer join: BU`ckK\(
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。 !X-9Ms}(d
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二、提升 `|nH1sHFq
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) rn;<HT
法一:select * into b from a where 1<>1 z<!O!wX_aI
法二:select top 0 * into b from a FC{})|yh
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2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) $!f!,fw+
insert into b(a, b, c) select d,e,f from b; 80C(H!^
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) Pb#P`L7OB
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 I!P4(3skAB
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. `xCOR
4、说明:子查询(表名1:a 表名2:b) D&/I1=\(
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) _BbvhWN&+
5、说明:显示文章、提交人和最后回复时间 58: :h.:
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b <:">mV+/
6、说明:外连接查询(表名1:a 表名2:b) =NadAyv
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c ;+a2\j+
7、说明:在线视图查询(表名1:a ) 6hO-H&r++
select * from (SELECT a,b,c FROM a) T where t.a > 1; &=X.*H%
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 u"`*DFjo*
select * from table1 where time between time1 and time2 b]T@gJ4H=
select a,b,c, from table1 where a not between 数值1 and 数值2 e4DMO*6
9、说明:in 的使用方法 802H$P^ps
select * from table1 where a [not] in ('值1','值2','值4','值6') \8e2?(@"k
10、说明:两张关联表,删除主表中已经在副表中没有的信息 nq1
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delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) Xwt`(h[u
11、说明:四表联查问题: HJIC<U
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]q^{C:W
12、说明:日程安排提前五分钟提醒 0Qnd6mb
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 wPX*%0]
13、说明:一条sql 语句搞定数据库分页 Br!9x{q*
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 V^TbP.
14、说明:前10条记录 6Z?Su(s(5
select top 10 * form table1 where 范围 O(c@PJem
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.) a7#?h%wf
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) l(!/Q|Q|
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 &l m#
(select a from tableA ) except (select a from tableB) except (select a from tableC) Qs%B'9")
17、说明:随机取出10条数据 5wv fF.v
select top 10 * from tablename order by newid() .t=
18、说明:随机选择记录 '1Y\[T*
select newid() eVJ^\z:4
19、说明:删除重复记录 }gv8au<
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) O6X"RsI}
20、说明:列出数据库里所有的表名 ((bTwx
select name from sysobjects where type='U' +.kfU)6@
21、说明:列出表里的所有的 P6\6?am
select name from syscolumns where id=object_id('TableName') [%pRfjM
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。 i{Ds&{
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-Qmx-N
显示结果: TB!(('
type vender pcs dg_G s>?2
电脑 A 1 Z6Fp\aI8@
电脑 A 1 9t$]X>}
光盘 B 2 b?T
光盘 A 2 ~b)74M/
手机 B 3 \)/yC74r7(
手机 C 3 LT VF8-v
23、说明:初始化表table1 ?!'ZfQ:zK
TRUNCATE TABLE table1 2VoKr)
24、说明:选择从10到15的记录 @7<uMasfp
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc [{
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三、技巧 j Ux
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1、1=1,1=2的使用,在SQL语句组合时用的较多 ?LK 2g
"where 1=1" 是表示选择全部 "where 1=2"全部不选, @~ETj26U'
如: i'#Gy,R
if @strWhere !='' {d<;BLA
begin j)C:$
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere )"+2Z^1-
end T~:|!`
else ])}(k
begin $O)3q
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set @strSQL = 'select count(*) as Total from [' + @tblName + ']' N<(.%<!
end >>{FzR
我们可以直接写成 ._O
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere 2lVHZ\G
2、收缩数据库 2L?!tBw?1
--重建索引 U}k9 Py
DBCC REINDEX CQh,~
DBCC INDEXDEFRAG VVP:w%yW
--收缩数据和日志 \>QF(J [8
DBCC SHRINKDB `n5"0QRd
DBCC SHRINKFILE !> }.~[M
3、压缩数据库 #~O b)q|
dbcc shrinkdatabase(dbname) qqrq11W
4、转移数据库给新用户以已存在用户权限 e[_m<e
exec sp_change_users_login 'update_one','newname','oldname' mtz#}qD66
go UFAL1c<V
5、检查备份集 /,=@8k!t?
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' 4;`oUt'.
6、修复数据库 l 'DsZ9y@2
ALTER DATABASE [dvbbs] SET SINGLE_USER uVyGk~
GO _BdE<
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DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK Ig]iT
GO n_ lo`
ALTER DATABASE [dvbbs] SET MULTI_USER Suk
GO h\v'9
7、日志清除 W"^wnGa@a
SET NOCOUNT ON t58e(dgi
DECLARE @LogicalFileName sysname, ]I3!fEAWR
@MaxMinutes INT, $un?0S
@NewSize INT
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USE tablename -- 要操作的数据库名 N_:qRpp6i
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 [ i#zP
@MaxMinutes = 10, -- Limit on time allowed to wrap log. $/!{OU.t`
@NewSize = 1 -- 你想设定的日志文件的大小(M) ;qH O OT
-- Setup / initialize M@0;B30L
DECLARE @OriginalSize int {ZY+L;eg1
SELECT @OriginalSize = size fd-q3_f
FROM sysfiles [q !TIq
WHERE name = @LogicalFileName <! )**
SELECT 'Original Size of ' + db_name() + ' LOG is ' + 5onm]V]
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + UfS%71l.$
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' pPd#N'\*
FROM sysfiles a7N!B' y
WHERE name = @LogicalFileName e[hcJz!D
CREATE TABLE DummyTrans lz1wO5%h
(DummyColumn char (8000) not null) ?-^~f
DECLARE @Counter INT, Kq i4hK
@StartTime DATETIME, _h}kp\sps
@TruncLog VARCHAR(255) 5mb]Q)f9-
SELECT @StartTime = GETDATE(), L:@7tc.
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' [l,Ei?
DBCC SHRINKFILE (@LogicalFileName, @NewSize) g<~Cpd
EXEC (@TruncLog) M)SEn/T-
-- Wrap the log if necessary. 9K1oZ?)_z
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired itC-4^
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) l\C.",CEcc
AND (@OriginalSize * 8 /1024) > @NewSize 72'5%*1
BEGIN -- Outer loop. M![J2=
SELECT @Counter = 0 jy'13G/b\
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) o"*AtGR+"
BEGIN -- update |P%Jw,}]9
INSERT DummyTrans VALUES ('Fill Log') =Q\r?(Iy
DELETE DummyTrans s_mS^`P7
SELECT @Counter = @Counter + 1 6'Fd GS
END MdW]MW{
EXEC (@TruncLog) p|!
END 9Q"'"b*?z
SELECT 'Final Size of ' + db_name() + ' LOG is ' + *c2YRbU(
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + I1X-s
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' b9l;a+]d
FROM sysfiles ^jx7@LgS=
WHERE name = @LogicalFileName ^0 -:G6H
DROP TABLE DummyTrans sIy^m}02
SET NOCOUNT OFF MjU6/pO}L
8、说明:更改某个表 ;5)P6S.D
exec sp_changeobjectowner 'tablename','dbo' &wV]"&-
9、存储更改全部表 %rv7Jy
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch adR)Uq9
@OldOwner as NVARCHAR(128), _WRFsDZ'
@NewOwner as NVARCHAR(128) -[wGX}}
AS z*!%g[3I
DECLARE @Name as NVARCHAR(128) V{!J-nO
DECLARE @Owner as NVARCHAR(128) y2^Y/)
DECLARE @OwnerName as NVARCHAR(128) H*r)Z90
DECLARE curObject CURSOR FOR 2I,^YWR
select 'Name' = name, C)`Fv=]R
'Owner' = user_name(uid) (^Y~/
from sysobjects XzEc2)0'v
where user_name(uid)=@OldOwner '2 PF
order by name N$U$5;r~`
OPEN curObject 3R.W>U
FETCH NEXT FROM curObject INTO @Name, @Owner G6$kv2(k`@
WHILE(@@FETCH_STATUS=0) ~=uWD&5B4
BEGIN v]B3m
if @Owner=@OldOwner ?j"KV_
begin 8; 0A
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set @OwnerName = @OldOwner + '.' + rtrim(@Name) +lHjC$
exec sp_changeobjectowner @OwnerName, @NewOwner H}hiT/+$
end ,g2ij
-- select @name,@NewOwner,@OldOwner )-a'{W/t
FETCH NEXT FROM curObject INTO @Name, @Owner "eB$k40-
END t.xxSU5~%
close curObject X:vghOt?
deallocate curObject JvVWG'Z"
GO ;V *l.gr'2
10、SQL SERVER中直接循环写入数据 5kCUaPu
declare @i int 2AT5
set @i=1 X\{LnZ@r4
while @i<30 zh8nc%X{
begin {>hC~L?6
insert into test (userid) values(@i) : y%d
set @i=@i+1 >7jbgHB
end 0jy2H2
小记存储过程中经常用到的本周,本月,本年函数 |)(VsVG&
Dateadd(wk,datediff(wk,0,getdate()),-1) 1v.c 6~
Dateadd(wk,datediff(wk,0,getdate()),6) Ya3C#=
Dateadd(mm,datediff(mm,0,getdate()),0) -p]1=@A<}
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) ~A'!2
Dateadd(yy,datediff(yy,0,getdate()),0) bDL,S?@
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) c;Pe/ d
上面的SQL代码只是一个时间段 J^SdH&%Z
Dateadd(wk,datediff(wk,0,getdate()),-1) k_
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Dateadd(wk,datediff(wk,0,getdate()),6) v%+:/m1
就是表示本周时间段. [q?<Qe
下面的SQL的条件部分,就是查询时间段在本周范围内的: :XZU&Sr"
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) ,(qRc(Ho
而在存储过程中 [>8}J"
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) a{^m-fSaR"
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) e7Xeo +/