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Sql Server根据记录集批量更新数据库

update   t1   set   t1.value=t2.value   from   t2   where   t1.id=t2.id
 
update jbsite_class  set topicnum = count
from (select t2.classid,count from (
select distinct classid,count(*) as count
from jbsite_product
group by classid) t2
inner join  jbsite_product on jbsite_product.id = t2.classid
) b where jbsite_class.id=b.classid


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PL/SQL学习笔记五


游标是从数据库中提取出来的数据,以临时表的形式存放在内存中,在游标中有一个数据指针,在初始状态下指向首记录, 利用fetch语句移动该指针,从而对游标中的数据进行各种操作。
1.定义游标
cursor 游标名 is select语句;
2.打开游标
open 游标名;
3.提取游标数据
fetch 游标名 into 变量名1, 变量名2, ....;
或 ......

SQL*Plus FAQ

 What is SQL*Plus and where does it come from?
SQL*Plus is a command line SQL and PL/SQL language interface and reporting tool that ships with the Oracle Database Client and Server software. It can be used interactively or driven from scripts. SQL*Plus is frequently used by DBAs and Developers ......

Oracle维护常用SQL语句汇总

Oracle维护常用SQL语句汇总
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如何远程判断Oracle数据库的安装平台
select * from v$version;
查看表空间的使用情况
select sum(bytes)/(1024*1024) as free_space,tablespace_name
from dba_free_space
group by tablespace_ ......

SQL重复记录查询删除

1
、查找表中多余的重复记录,重复记录是根据单个字段(peopleId)来判断
select

*

from
people
where
peopleId
in
(
select
   peopleId  
from
   people  
group
  
by
   peopleId  
having
  
cou ......

三种SQL分页方式


1.分页方案一:(利用Not In和SELECT TOP分页)
  语句形式:
SELECTTOP10*fromTestTableWHERE(IDNOTIN     (SELECTTOP20id    fromTestTable    ORDERBYid))ORDERBYIDSELECTTOP页大小*fromTestTableWHERE(IDNOTIN     (SELECTTOP页大小*页数id    from表    ORDERBYid))ORDERBYID
  2.分 ......
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