选择MAX（）以获取特定值 [英] Select MAX() for a specific value

问题描述

您好，



我尝试从具有特定值的表中选择MAX日期，类似于：

  SELECT  regRaport.regRaport_id，regRaport.regRaport_date，regRaport.regRaport_soldinitial，regRaport.regRaport_soldfinal，IIF（regRaport。 regRaport_categorie    Null ， 0 ，regRaport。 regRaport_categorie） AS  RegRaportCategorie 
  FROM  regRaport 
  WHERE  regRaport.regRaport_date =（ select  MAX（regRaport.regRaport_date）来自 regRaport < span class =code-keyword> WHERE  regRaport_categorie = 5）; 

但上面的查询返回所有值MAX（）日期，不适用于特定类别。

有什么建议吗？

解决方案

试试这个

  SELECT  regRaport.regRaport_id，
 regRaport.regRaport_date，
 regRaport.regRaport_soldinitial，
 regRaport.regRaport_soldfinal，
 IIF（regRaport.regRaport_categorie    Null ， 0 ，regRaport.regRaport_categorie） AS  RegRaportCategorie 
  FROM  regRaport 
  inner   join （ select  regRaport.regRaport_id  as  ID ，
 MAX（regRaport.regRaport_date） as  regDate 
 来自 regRaport 
  WHERE  regRaport_categorie =  5 ）r例如
  on  regRaport.regRaport_id = reg.ID 
 和 regRaport.regRaport_date = reg.regDate 

Hello,

I try to select the MAX date from a table who has a specific value, something like that:

SELECT regRaport.regRaport_id, regRaport.regRaport_date, regRaport.regRaport_soldinitial, regRaport.regRaport_soldfinal, IIF(regRaport.regRaport_categorie Is Null, 0, regRaport.regRaport_categorie) AS RegRaportCategorie
FROM regRaport
WHERE regRaport.regRaport_date=(select MAX(regRaport.regRaport_date) from regRaport  WHERE regRaport_categorie=5);

but the above query returns all value for MAX() date, not for a specific category.
Any suggestions?

解决方案

Try this

SELECT	regRaport.regRaport_id,
	regRaport.regRaport_date,
	regRaport.regRaport_soldinitial,
	regRaport.regRaport_soldfinal,
	IIF(regRaport.regRaport_categorie Is Null, 0, regRaport.regRaport_categorie) AS RegRaportCategorie
FROM	regRaport
inner join (select regRaport.regRaport_id as ID,
				MAX(regRaport.regRaport_date) as regDate
		from	regRaport
		WHERE	regRaport_categorie = 5) reg
	on  regRaport.regRaport_id = reg.ID
	and regRaport.regRaport_date = reg.regDate

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