我需要使用 php - mysql 列出产品的唯一最新版本

Question

I'm just trying to list the only latest versions of the products. Not all versions with the same product name.

So this:

Instead of this:

* tables are not so important I just want the code to get the data.
* tables are not so important I just want the code to get the data.

This is my code but lists nothing :

include("databaseinfo.php");
$sql = "SELECT product_name,release_date,version FROM product GROUP BY product_name ORDER BY product_ID DESC";
$result = mysqli_query($conn,$sql);
while ($b=mysqli_fetch_array($result,MYSQLI_ASSOC)){
    echo $b['product_name']." ".$b['release_date']." ".$b['version'];
}

My product table:

Answer 1

One option is to filter with a subquery:

select product_name, release_date, version
from product p
where release_date = (
    select max(p1.release_date)
    from product p1
    where p1.product_id = p.product_id
)

If you are running MySQL 8.0, you can also use rank() :

select product_name, release_date, version
from (
    select p.*, rank() over(partition by product_id order by release_date desc)
    from product
) t
where rn = 1

This assumes that product_id uniquely identifies each product (so your table would have several rows per product_id ) - if that's not the case, use product_name instead.