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。 q>q:ZV
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一、基础 >%JPgr/
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1、说明:创建数据库 Otn,UoeeB
CREATE DATABASE database-name ?I.9?cQXZ
2、说明:删除数据库 x^f<G
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drop database dbname FB=oGgwwq
3、说明:备份sql server R{hX--|j
--- 创建 备份数据的 device bIKg>U'5d
USE master gU9{~-9}
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' X@nBj;
--- 开始 备份 mgxIxusR
BACKUP DATABASE pubs TO testBack T?9D?u?]
4、说明:创建新表 *P()&}JK
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) NOz3_k
根据已有的表创建新表: @0`A!5h?u
A:create table tab_new like tab_old (使用旧表创建新表) TFVQfj$r
B:create table tab_new as select col1,col2... from tab_old definition only ,N/@=As9$
5、说明:删除新表 D{|q P
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drop table tabname E3L?6Qfx>
6、说明:增加一个列 vNv?trw
Alter table tabname add column col type T}~TW26v
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。 BT{;^Hp
7、说明:添加主键: Alter table tabname add primary key(col) J=V
说明:删除主键: Alter table tabname drop primary key(col) gmTBT#{6yH
8、说明:创建索引:create [unique] index idxname on tabname(col....) wZrFu(_
删除索引:drop index idxname xQ?>72grP
注:索引是不可更改的,想更改必须删除重新建。 g14*6O:
9、说明:创建视图:create view viewname as select statement 1I Yip\:lS
删除视图:drop view viewname Pms@!yce
10、说明:几个简单的基本的sql语句 ^<]'?4m]
选择:select * from table1 where 范围 [^>XRBSm
插入:insert into table1(field1,field2) values(value1,value2) a"~o'W7
删除:delete from table1 where 范围 _8K+iqMZG
更新:update table1 set field1=value1 where 范围 z,HhSW?&^
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! }v(wjD
排序:select * from table1 order by field1,field2 [desc] 6*8Wtq
总数:select count as totalcount from table1 vr!J3H f
求和:select sum(field1) as sumvalue from table1 a+h$u
平均:select avg(field1) as avgvalue from table1 <+8'H:wz
最大:select max(field1) as maxvalue from table1 0V%c%]PH
最小:select min(field1) as minvalue from table1 6K2e]r
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11、说明:几个高级查询运算词 rK~-Wzwu
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A: UNION 运算符 \BOoY# !a
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 ,|%KlHo^
B: EXCEPT 运算符 3CUQQ_
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 I-v}
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C: INTERSECT 运算符 I?KN7(9u?
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 ~W'DEpq_
注:使用运算词的几个查询结果行必须是一致的。 P\7DA4]
12、说明:使用外连接 Z0|5VLk,<{
A、left outer join: pP\Cwo #,
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 !3Dq)ebBz
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c 5zuwqOD*
B:right outer join: sYTz6-
右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 r}U6LE?>
C:full outer join: C* `WMP*
全外连接:不仅包括符号连接表的匹配行,还包括两个连接表中的所有记录。 l,ny=Q$[1'
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二、提升 g/?Vl2W
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) j*=!M# D
法一:select * into b from a where 1<>1 #h!+b
法二:select top 0 * into b from a c
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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) |jsI-?%8J
insert into b(a, b, c) select d,e,f from b; verI~M$v{
3、说明:跨数据库之间表的拷贝(具体数据使用绝对路径) (Access可用) kuY^o,u-1e
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 YMGy-]!o
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. 0JR/V68$
4、说明:子查询(表名1:a 表名2:b) ~$!,-r
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) B5\l&4X
5、说明:显示文章、提交人和最后回复时间 wG3L+[,
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b .=y=Fv6X
6、说明:外连接查询(表名1:a 表名2:b) 7j&
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select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c .5JIQWE(
7、说明:在线视图查询(表名1:a ) = XZU9df
select * from (SELECT a,b,c FROM a) T where t.a > 1; /"m s
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 5hs_k[q
select * from table1 where time between time1 and time2 ]l7W5$26 @
select a,b,c, from table1 where a not between 数值1 and 数值2 Po>6I0y
9、说明:in 的使用方法 SA,~q&
select * from table1 where a [not] in ('值1','值2','值4','值6') t@KTiJI
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10、说明:两张关联表,删除主表中已经在副表中没有的信息 +Z#=z,.^
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) K5>3
11、说明:四表联查问题: eAHY/Y!
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... o.s'0xP]
12、说明:日程安排提前五分钟提醒 (6,:X
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 ZbRRDXk!
13、说明:一条sql 语句搞定数据库分页 )1 <0c@g=
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 PW*Vfjf4
14、说明:前10条记录 A#>wbHjWF
select top 10 * form table1 where 范围 5-dt0I@<
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) g&RpE41x
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) "2e3 <:$
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 X[z;P!U
(select a from tableA ) except (select a from tableB) except (select a from tableC) pj'gTQ),0
17、说明:随机取出10条数据 ODJ"3 J
select top 10 * from tablename order by newid() N=mvr&arP
18、说明:随机选择记录 f/\!=sa:
select newid() q4BXrEOw
19、说明:删除重复记录 &+9 ;
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) &oL"AJU
20、说明:列出数据库里所有的表名 xvGYd,dlK
select name from sysobjects where type='U' z/Lb1ND8
21、说明:列出表里的所有的 88Pt"[{1
select name from syscolumns where id=object_id('TableName') hV3]1E21"
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。 Ff<cY%t
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 g4W$MI
显示结果: vc#o(?g
type vender pcs _z_YJ7A>
电脑 A 1 `&;#A*C0
电脑 A 1 ^!['\
光盘 B 2 [*%lm9 x
光盘 A 2 >N3X/8KL%
手机 B 3 EeaJUK]z9
手机 C 3 C&O8fNB_
23、说明:初始化表table1 )Rr6@o
TRUNCATE TABLE table1 ,Csdon
24、说明:选择从10到15的记录 3h
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select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc >WHajYO"
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三、技巧 j;$f[@0o
1、1=1,1=2的使用,在SQL语句组合时用的较多 jMT[+f
"where 1=1" 是表示选择全部 "where 1=2"全部不选,
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如: %6ckau1_;
if @strWhere !='' }3
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begin 'O%*:'5k
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere HoBx0N9\2
end rpk8
else GTs,?t16/
begin tmGhJZ2j
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' GEPWb[Oa
end '[
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我们可以直接写成 F'~r?D
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere <h(AJX7wsD
2、收缩数据库 R;"$ PHD
--重建索引 h(WlJCln
DBCC REINDEX <n_?$ TJ
DBCC INDEXDEFRAG a-*sm~u
--收缩数据和日志 %+r(*Q+0$f
DBCC SHRINKDB ^;II@n
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DBCC SHRINKFILE hC-uz _/3
3、压缩数据库 hu-]SGb6
dbcc shrinkdatabase(dbname) M:O*_>KF
4、转移数据库给新用户以已存在用户权限 +5fB?0D;
exec sp_change_users_login 'update_one','newname','oldname' F%L"Q>aHW
go Eu|/pH=:
5、检查备份集 fMwF|;
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' qJ" (:~
6、修复数据库 .J.}}"+U
ALTER DATABASE [dvbbs] SET SINGLE_USER :7@[=n
GO f y|JE9Io_
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK hn .(pI1
GO *gmc6xY
ALTER DATABASE [dvbbs] SET MULTI_USER TJ)Nr*U3_
GO ->#wDL!6
7、日志清除 sta/i?n
SET NOCOUNT ON s-#@t
DECLARE @LogicalFileName sysname, MdX4Rp'
@MaxMinutes INT, yCz"~c
@NewSize INT Rd(8j+Q?ps
USE tablename -- 要操作的数据库名 [KUkv
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 `&I6=,YLp
@MaxMinutes = 10, -- Limit on time allowed to wrap log. ~ESw* 6s9
@NewSize = 1 -- 你想设定的日志文件的大小(M) j1Ys8k%$l
-- Setup / initialize {9J|\Zz3
DECLARE @OriginalSize int W3l[a^1d
SELECT @OriginalSize = size d{TcjZ
FROM sysfiles +@$VJM%^7b
WHERE name = @LogicalFileName l|842N@1
SELECT 'Original Size of ' + db_name() + ' LOG is ' + Ov"wcJ
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + -raK
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' \,v^v]|
FROM sysfiles YBY;$&9
WHERE name = @LogicalFileName zGe =l;
CREATE TABLE DummyTrans fq1w <e
(DummyColumn char (8000) not null) 6l|L/Z_6
DECLARE @Counter INT, ?23J(;)s
@StartTime DATETIME, )^UqB0C6^
@TruncLog VARCHAR(255) dLQp"vs $
SELECT @StartTime = GETDATE(), +:m)BLA4l
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' @3eMvbI
DBCC SHRINKFILE (@LogicalFileName, @NewSize) \;%D;3Au
EXEC (@TruncLog) =ZHN]PP
-- Wrap the log if necessary. yI=nu53BV
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired Z4z|B&
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) (9bU\4F\
AND (@OriginalSize * 8 /1024) > @NewSize 5I* 1CIO
BEGIN -- Outer loop. uA`e
SELECT @Counter = 0 vkLt#yj~
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) W)`>'X`
BEGIN -- update EQnU:a
INSERT DummyTrans VALUES ('Fill Log') Ym%#"
DELETE DummyTrans 6n:X
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SELECT @Counter = @Counter + 1 7<kr|-
END w2$ L;q
EXEC (@TruncLog) 2C0j.Ib
END 2SC'Z>A
SELECT 'Final Size of ' + db_name() + ' LOG is ' + p;[.&oJ
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + H/f}tw
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' ,>g(%3C
FROM sysfiles PazWMmI
WHERE name = @LogicalFileName ldG8hK
DROP TABLE DummyTrans HJr*\%D}1
SET NOCOUNT OFF MPp:EH
8、说明:更改某个表 (*26aMp
exec sp_changeobjectowner 'tablename','dbo' YTgT2w
9、存储更改全部表 q.:a4w J
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch qHrIs-NR
@OldOwner as NVARCHAR(128), 5m;pHgkb
@NewOwner as NVARCHAR(128) p-C{$5&
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AS h1)+QLI
DECLARE @Name as NVARCHAR(128) aorL ,l
DECLARE @Owner as NVARCHAR(128) AB!({EIi
DECLARE @OwnerName as NVARCHAR(128) T5@t_D>8
DECLARE curObject CURSOR FOR +=`w
select 'Name' = name, {3Gj
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'Owner' = user_name(uid) yokZ>+jb
from sysobjects \#h=pz+jb
where user_name(uid)=@OldOwner Jx3a7CpX
order by name 7DW-brd
OPEN curObject )W @
FETCH NEXT FROM curObject INTO @Name, @Owner L7II>^"B
WHILE(@@FETCH_STATUS=0) ^wIP`dn
BEGIN "{{@N4^
if @Owner=@OldOwner PzjIM!>
begin Ux,dj8=o
set @OwnerName = @OldOwner + '.' + rtrim(@Name) F&/}x15
exec sp_changeobjectowner @OwnerName, @NewOwner TR?jT
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end B_r:da CS:
-- select @name,@NewOwner,@OldOwner 7|m{hSc
FETCH NEXT FROM curObject INTO @Name, @Owner 8Z@O%\1x6
END L8;`*H
close curObject e mq%"
;.
deallocate curObject +SRM?av
GO ieyqp~+|4$
10、SQL SERVER中直接循环写入数据 ^J?2[(
declare @i int KE)^S
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set @i=1 j{5oXW
while @i<30 XF4NRs
begin RvW>kATb_F
insert into test (userid) values(@i) m[5ed1+
set @i=@i+1 lKirc2
end UR`pZ.U?
小记存储过程中经常用到的本周,本月,本年函数 @[(%b{TE;
Dateadd(wk,datediff(wk,0,getdate()),-1) :Ea]baM"
Dateadd(wk,datediff(wk,0,getdate()),6) {-IRX)m*
Dateadd(mm,datediff(mm,0,getdate()),0) YkV-]%c
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) %D^j7`Z
Dateadd(yy,datediff(yy,0,getdate()),0) _*(:6,8
Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) WtSlD9 h
上面的SQL代码只是一个时间段 7_7^&.Hh
Dateadd(wk,datediff(wk,0,getdate()),-1) {*|$@%y!
Dateadd(wk,datediff(wk,0,getdate()),6) Z=?qf$.}
就是表示本周时间段. avv/mEf-f
下面的SQL的条件部分,就是查询时间段在本周范围内的: /3vj`#jD
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) 4p&SlJ
而在存储过程中 nYY' hjZ
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) MU_
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select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) b~G|Bhxa