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。 H9m2Whq
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一、基础 soK_l|z:J
1、说明:创建数据库 \D k^\-
CREATE DATABASE database-name =y/Lbe}:
2、说明:删除数据库 h pes
drop database dbname O.f3 (e!
3、说明:备份sql server X?xm1|\
--- 创建 备份数据的 device c@{^3V##T
USE master aZ3 #g
EXEC sp_addumpdevice 'disk', 'testBack', 'c:\mssql7backup\MyNwind_1.dat' UHszOl
--- 开始 备份 _IGa8=~
BACKUP DATABASE pubs TO testBack TK?N^ly
4、说明:创建新表 {$=%5
create table tabname(col1 type1 [not null] [primary key],col2 type2 [not null],..) BqA wo
根据已有的表创建新表: X"59`Yh
A:create table tab_new like tab_old (使用旧表创建新表) %31K*i/]
B:create table tab_new as select col1,col2... from tab_old definition only ?O^:j!C6
5、说明:删除新表 qGUe0(
drop table tabname <.XoC?j
6、说明:增加一个列 ,(?4T~
Alter table tabname add column col type RwHXn]1
注:列增加后将不能删除。DB2中列加上后数据类型也不能改变,唯一能改变的是增加varchar类型的长度。 Os]M$c_88
7、说明:添加主键: Alter table tabname add primary key(col) j~>
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说明:删除主键: Alter table tabname drop primary key(col) qiJ;v1
8、说明:创建索引:create [unique] index idxname on tabname(col....) j0NPd^
删除索引:drop index idxname <[??\YOc
注:索引是不可更改的,想更改必须删除重新建。 *Z(C')7r
9、说明:创建视图:create view viewname as select statement 9
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删除视图:drop view viewname e';c8WF3E
10、说明:几个简单的基本的sql语句 [<Puh
选择:select * from table1 where 范围 #yxYL0CcA:
插入:insert into table1(field1,field2) values(value1,value2) hpKc_|un
删除:delete from table1 where 范围 :WTvP$R
更新:update table1 set field1=value1 where 范围 S$:S*6M@"
查找:select * from table1 where field1 like '%value1%' ---like的语法很精妙,查资料! KAEpFobYo
排序:select * from table1 order by field1,field2 [desc] O3GaxM\x
总数:select count as totalcount from table1 td$Jx}'A
求和:select sum(field1) as sumvalue from table1 #Ih(2T
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平均:select avg(field1) as avgvalue from table1 }eK*)
最大:select max(field1) as maxvalue from table1 \zDV|n~{w
最小:select min(field1) as minvalue from table1 ZI]K+jza
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11、说明:几个高级查询运算词 ds[~Cp
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A: UNION 运算符 }+3~y'k
UNION 运算符通过组合其他两个结果表(例如 TABLE1 和 TABLE2)并消去表中任何重复行而派生出一个结果表。当 ALL 随 UNION 一起使用时(即 UNION ALL),不消除重复行。两种情况下,派生表的每一行不是来自 TABLE1 就是来自 TABLE2。 2Rt ZTn
B: EXCEPT 运算符 @3D%i#2o&[
EXCEPT 运算符通过包括所有在 TABLE1 中但不在 TABLE2 中的行并消除所有重复行而派生出一个结果表。当 ALL 随 EXCEPT 一起使用时 (EXCEPT ALL),不消除重复行。 zOp"n\
C: INTERSECT 运算符 S(xA}0]
INTERSECT 运算符通过只包括 TABLE1 和 TABLE2 中都有的行并消除所有重复行而派生出一个结果表。当 ALL 随 INTERSECT 一起使用时 (INTERSECT ALL),不消除重复行。 i<![i5uAI
注:使用运算词的几个查询结果行必须是一致的。 ]c+'SJQ
12、说明:使用外连接 >u[ln@ l
A、left outer join: </Lqk3S-!
左外连接(左连接):结果集几包括连接表的匹配行,也包括左连接表的所有行。 hZG{"O!2s
SQL: select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c P3>2=qK"E(
B:right outer join: 8\_,Y
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右外连接(右连接):结果集既包括连接表的匹配连接行,也包括右连接表的所有行。 AG=1TZI"
C:full outer join: >qZRIDE5$
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。 mJqP#Unik
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二、提升 }RK9Onh3G
1、说明:复制表(只复制结构,源表名:a 新表名:b) (Access可用) |%9~W^b
法一:select * into b from a where 1<>1 [a6lE"yr
法二:select top 0 * into b from a 3F3?be
2、说明:拷贝表(拷贝数据,源表名:a 目标表名:b) (Access可用) >0$5H]1u
insert into b(a, b, c) select d,e,f from b; L1+cv;t
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) pgi7 JQ
insert into b(a, b, c) select d,e,f from b in '具体数据库' where 条件 pYQs|5d
例子:..from b in '"&Server.MapPath(".")&"\data.mdb" &"' where.. S)h1e%f,
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4、说明:子查询(表名1:a 表名2:b) QY!A[!6h
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) HX[#tT|m~
5、说明:显示文章、提交人和最后回复时间 jlZNANR3
select a.title,a.username,b.adddate from table a,(select max(adddate) adddate from table where table.title=a.title) b 7MfvU|D[d/
6、说明:外连接查询(表名1:a 表名2:b) Jl}7]cVq#
select a.a, a.b, a.c, b.c, b.d, b.f from a LEFT OUT JOIN b ON a.a = b.c {)xrg sB
7、说明:在线视图查询(表名1:a ) b`=rd 4cpU
select * from (SELECT a,b,c FROM a) T where t.a > 1; M?97F!\U
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 8i"fhN3?Y
select * from table1 where time between time1 and time2 Rh^$0Q*2
select a,b,c, from table1 where a not between 数值1 and 数值2 2|EoP-K7
9、说明:in 的使用方法 5lbh
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select * from table1 where a [not] in ('值1','值2','值4','值6') fA5#
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10、说明:两张关联表,删除主表中已经在副表中没有的信息 %vzpp\t
delete from table1 where not exists ( select * from table2 where table1.field1=table2.field1 ) jws(`mIf\
11、说明:四表联查问题: 1uE[ %M
select * from a left inner join b on a.a=b.b right inner join c on a.a=c.c inner join d on a.a=d.d where ..... }zi6 F.
12、说明:日程安排提前五分钟提醒 ~yg9ZM
SQL: select * from 日程安排 where datediff('minute',f开始时间,getdate())>5 _^ZII
13、说明:一条sql 语句搞定数据库分页 % *hBrjbj
select top 10 b.* from (select top 20 主键字段,排序字段 from 表名 order by 排序字段 desc) a,表名 b where b.主键字段 = a.主键字段 order by a.排序字段 B dUyI_Ks:
14、说明:前10条记录 6<R
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select top 10 * form table1 where 范围 &kt#p;/p?
15、说明:选择在每一组b值相同的数据中对应的a最大的记录的所有信息(类似这样的用法可以用于论坛每月排行榜,每月热销产品分析,按科目成绩排名,等等.) VI{1SIhfa
select a,b,c from tablename ta where a=(select max(a) from tablename tb where tb.b=ta.b) +!wc(N[(2
16、说明:包括所有在 TableA 中但不在 TableB和TableC 中的行并消除所有重复行而派生出一个结果表 N*;/~bt7P
(select a from tableA ) except (select a from tableB) except (select a from tableC) 4|UIyDt8
17、说明:随机取出10条数据 Pr"ESd>Y
select top 10 * from tablename order by newid() (C|%@6 1S
18、说明:随机选择记录 zyE yZc?
select newid() v%w]Q B
19、说明:删除重复记录 fk_i~K
Delete from tablename where id not in (select max(id) from tablename group by col1,col2,...) .l!Z=n|
20、说明:列出数据库里所有的表名 ^
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select name from sysobjects where type='U' 9`{cX
21、说明:列出表里的所有的 'rgV]Oy
select name from syscolumns where id=object_id('TableName') vJ s/ett
22、说明:列示type、vender、pcs字段,以type字段排列,case可以方便地实现多重选择,类似select 中的case。 7#`:m|$
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 "~6BC
显示结果: k5/}S@F8
type vender pcs t!$/r]XM h
电脑 A 1 :yeTzIz]
电脑 A 1 ?T&D@Ohsx
光盘 B 2 shRvwE[
光盘 A 2 r}w 9?s^rB
手机 B 3 Kk#@8h>
手机 C 3 wO9<An
23、说明:初始化表table1 O)?0G$0
TRUNCATE TABLE table1 s Y,3
24、说明:选择从10到15的记录 el<nY"c
select top 5 * from (select top 15 * from table order by id asc) table_别名 order by id desc rkrt.B
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三、技巧 }9JPSl28Jr
1、1=1,1=2的使用,在SQL语句组合时用的较多 }HzZj;O^2>
"where 1=1" 是表示选择全部 "where 1=2"全部不选, 0ni5 :tYy
如: B^Q#@[T
if @strWhere !='' t&0p@xLQ
begin (`N/1}vk
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where ' + @strWhere
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end 4KKNw9L)
else d:aQlW;}
begin \GN5Sy]r
set @strSQL = 'select count(*) as Total from [' + @tblName + ']' JqO( ]*"Hi
end $i hIHl6'
我们可以直接写成 C%&7,F7
set @strSQL = 'select count(*) as Total from [' + @tblName + '] where 1=1 安定 '+ @strWhere :>5]A6Wi
2、收缩数据库 ~tWBCq 6
--重建索引 >_".
DBCC REINDEX 5VN4A<))
DBCC INDEXDEFRAG ??Lxb% 7R
--收缩数据和日志 dK-G%5)r
DBCC SHRINKDB W~qo
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DBCC SHRINKFILE =W6P>r_
3、压缩数据库 :zCm$@
dbcc shrinkdatabase(dbname) fHiCuF
4、转移数据库给新用户以已存在用户权限 mTt 9 o9E
exec sp_change_users_login 'update_one','newname','oldname' T
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go E_z@\z MB
5、检查备份集 Zo`^pQS
RESTORE VERIFYONLY from disk='E:\dvbbs.bak' )xeVoAg
6、修复数据库 7hc(]8eP
ALTER DATABASE [dvbbs] SET SINGLE_USER BBDOjhik
GO `u-}E9{
DBCC CHECKDB('dvbbs',repair_allow_data_loss) WITH TABLOCK n\ZFPXP
GO 5"sF#Y&
ALTER DATABASE [dvbbs] SET MULTI_USER ifkA3]
GO 0-FbV,:;
7、日志清除 +RM3EvglDQ
SET NOCOUNT ON cGDA0#r
DECLARE @LogicalFileName sysname, (8{Z@
@MaxMinutes INT, (]JJ?aAF
@NewSize INT %+.]>''a
USE tablename -- 要操作的数据库名 S'WmPv
SELECT @LogicalFileName = 'tablename_log', -- 日志文件名 j EX([J1
@MaxMinutes = 10, -- Limit on time allowed to wrap log. =F`h2 A;a
@NewSize = 1 -- 你想设定的日志文件的大小(M) gm8H)y,
-- Setup / initialize ^a]:GPc
DECLARE @OriginalSize int nL$tXm-x
SELECT @OriginalSize = size Au
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FROM sysfiles >TE&myZ?*
WHERE name = @LogicalFileName biJU r^n
SELECT 'Original Size of ' + db_name() + ' LOG is ' + %ug`dZ/
CONVERT(VARCHAR(30),@OriginalSize) + ' 8K pages or ' + 5H79) n>
CONVERT(VARCHAR(30),(@OriginalSize*8/1024)) + 'MB' OygYP
FROM sysfiles ?E`J-ncP
WHERE name = @LogicalFileName _tjH=Ff$
CREATE TABLE DummyTrans %w@(V([(c
(DummyColumn char (8000) not null) 9}4L8?2
DECLARE @Counter INT, qIk6S6
@StartTime DATETIME, i|<*EXB"
@TruncLog VARCHAR(255) 4bO7rhve
SELECT @StartTime = GETDATE(), ?;$g, 2n
@TruncLog = 'BACKUP LOG ' + db_name() + ' WITH TRUNCATE_ONLY' DN!EsQ6
DBCC SHRINKFILE (@LogicalFileName, @NewSize) T]:5y_4?[
EXEC (@TruncLog) `s+qz
-- Wrap the log if necessary. 6x{B
WHILE @MaxMinutes > DATEDIFF (mi, @StartTime, GETDATE()) -- time has not expired aRV<y8{9
AND @OriginalSize = (SELECT size FROM sysfiles WHERE name = @LogicalFileName) 1F=x~FMvY
AND (@OriginalSize * 8 /1024) > @NewSize 6};Sn/8
BEGIN -- Outer loop. HdGy$m`
SELECT @Counter = 0 ev; &$Hc
WHILE ((@Counter < @OriginalSize / 16) AND (@Counter < 50000)) O&)Y3 O1
BEGIN -- update 33; ytd
INSERT DummyTrans VALUES ('Fill Log') xsa*
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DELETE DummyTrans 5=dg4"b]
SELECT @Counter = @Counter + 1 !vsUL-
END 0ul2rZc
EXEC (@TruncLog) Pvtf_Qo^
END '
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SELECT 'Final Size of ' + db_name() + ' LOG is ' + X9P-fF?0
CONVERT(VARCHAR(30),size) + ' 8K pages or ' + PBUc9/
CONVERT(VARCHAR(30),(size*8/1024)) + 'MB' )a.U|[:y[+
FROM sysfiles .8,lhcpY
WHERE name = @LogicalFileName !,\]> c
DROP TABLE DummyTrans N=wB1gJ
SET NOCOUNT OFF &W ~,q(
8、说明:更改某个表 XW19hG
exec sp_changeobjectowner 'tablename','dbo' <%!@cE+y
9、存储更改全部表 F4k`x/ak
CREATE PROCEDURE dbo.User_ChangeObjectOwnerBatch ^ PD a
@OldOwner as NVARCHAR(128), 0$UE|yDs>
@NewOwner as NVARCHAR(128) Z6Mh`:7
AS al5?w{us
DECLARE @Name as NVARCHAR(128) R4o_zwWgPw
DECLARE @Owner as NVARCHAR(128) / og'W j
DECLARE @OwnerName as NVARCHAR(128) X<1# )xC
DECLARE curObject CURSOR FOR ~h1'_0t
select 'Name' = name, ]-O:| q>]
'Owner' = user_name(uid) Q{>{ e3z}
from sysobjects A5z`3T;1
where user_name(uid)=@OldOwner <EE)d@%>v
order by name %9M_*]
OPEN curObject WB= gN:?
FETCH NEXT FROM curObject INTO @Name, @Owner S]<Hx_[}
WHILE(@@FETCH_STATUS=0) NZ
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BEGIN :+u?A
if @Owner=@OldOwner b&!X#3(KT
begin $idYG<],
set @OwnerName = @OldOwner + '.' + rtrim(@Name) @ )1u
exec sp_changeobjectowner @OwnerName, @NewOwner <)rol
end Oh|Hy/&6W
-- select @name,@NewOwner,@OldOwner j/9'L^]
FETCH NEXT FROM curObject INTO @Name, @Owner a.q=
END SL*B `P~{
close curObject m:'fk;khN
deallocate curObject N!,@}s
GO zW\&q!`IRP
10、SQL SERVER中直接循环写入数据 #t;@x_2yD\
declare @i int -qs9a}iL
set @i=1 WT1ch0~2
while @i<30 P[D^*}
begin H3&$: h
insert into test (userid) values(@i) A$
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set @i=@i+1 vmL0H)q
end {|
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小记存储过程中经常用到的本周,本月,本年函数 rtOXK4)]I
Dateadd(wk,datediff(wk,0,getdate()),-1) pwm]2}+
Dateadd(wk,datediff(wk,0,getdate()),6) Xbfn@7m
Dateadd(mm,datediff(mm,0,getdate()),0) EKgTRRW
Dateadd(ms,-3,dateadd(mm,datediff(m,0,getdate())+1,0)) HogT#BMs
Dateadd(yy,datediff(yy,0,getdate()),0) p0[
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Dateadd(ms,-3,DATEADD(yy, DATEDIFF(yy,0,getdate())+1, 0)) "/wZt c
上面的SQL代码只是一个时间段 ]81P<Y(7
Dateadd(wk,datediff(wk,0,getdate()),-1) 6VIi
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Dateadd(wk,datediff(wk,0,getdate()),6) d?'q(6&H
就是表示本周时间段. uP<tP:
下面的SQL的条件部分,就是查询时间段在本周范围内的: *;Sj&O
Where Time BETWEEN Dateadd(wk,datediff(wk,0,getdate()),-1) AND Dateadd(wk,datediff(wk,0,getdate()),6) @<;0h|
而在存储过程中 w;)@2}
select @begintime = Dateadd(wk,datediff(wk,0,getdate()),-1) !AgW@
select @endtime = Dateadd(wk,datediff(wk,0,getdate()),6) 85-00m ~