Question

I’ve got some problem. I have 3 tables Product, Version, Date.

Dependencies:

• version.ProductId = Product.Id (there are >=1 versions of one product)
• Date.VersionId = Version.ID (one to one)

I want to get pairs product – version where Date of Version is Max (for each product)

Something like:

Product 1 - 1.0
Product 2 - 0.9 etc

I tried with the following query :

SELECT 
     productName, versionName
FROM   
    (SELECT 
         p.Name AS productName, v.Name AS versionName, MAX(d.Date) AS ddate
     FROM  
         Product AS p 
     INNER JOIN 
         Version AS v ON v.ProductId = p.Id 
     INNER JOIN 
         Date AS d ON d.VersionId = v.Id
     WHERE  
         (d.Date < { fn CURDATE() })
     GROUP BY p.Name) AS prd

But I get an error:

Column Version.Name is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause.

How to handle that ?

Answer 1

You need to include v.Name in the group by clause

SELECT productName, versionName 
FROM   
    (SELECT p.Name AS productName, v.Name AS versionName, MAX(d.Date) AS ddate 
    FROM  Product AS p INNER JOIN Version AS v ON v.ProductId = p.Id  
    INNER JOIN VDate AS d ON d.VersionId = v.Id 
    WHERE  (d.Date < { fn CURDATE() }) 
    GROUP BY p.Name, v.Name 
    ) AS prd 

Edit.

 select
product.name,
version.name
  from 
product
    inner join
      version
    on product.id = version.productid
inner join
    date on version.id = date.versionid
inner join 
(
    select productid, MAX(date) as maxdate
    from version
        inner join date on version.id = date.versionid
    group by productid
) maxver
    on date.date = maxver.maxdate
    and version.productid = maxver.productid