MySQL display records from one table as columns from another

I got the list you need, with the instruction case when and sum

select ar.id, ar.descripcion, ar.color, 
  sum(case when at.nombre = "alto"  then valor end) as alto,
  sum(case when at.nombre = "ancho" then valor end) as ancho,
  sum(case when at.nombre = "peso"  then valor end) as peso,
  sum(case when at.nombre = "stock" then valor end) as stock 
from articulos ar inner join atributos at
              on ar.id = at.id_art 
group by 1,2,3 ;

Good, the most accessible solution to your problem (to my way of seeing) is to perform a JOIN, (you can get more information about JOIN types here ). Note that if you had organized the column by assigning the name and then giving the values (respecting the id of articles), it would be much simpler (and logical).

Basically the query (that comes to mind) that most closely approximates what you want is:

SELECT * FROM articulos JOIN atributos ON articulos.id = atributos.id_art WHERE atributos.id_art = 1 AND IF (atributos.nombre = 'alto' AND atributos.valor = 150,TRUE,FALSE) OR IF(atributos.nombre = 'ancho' AND atributos.valor = 300,TRUE,FALSE)

The answer to this query (based on the data in your table) are the values: width = 300 and height = 150 (see image), confirming that these values exist for the article (id.art) 1.

Graphic example (click on the image to see better):

That is, for this case, the box complies with the two attributes, since if it did not have, for example, a height of 150, only width = 300 would appear, confirming that it does not meet both requirements.

That is, it works 'in reverse'.

SELECT a.Id, a.descripcion, a.color, a2.nombre, a2.valor  
FROM articulos AS a
INNER JOIN atributos AS a2
    ON (a.Id = a2.Id_art)
WHERE (a2.nombre = 'alto' and a2.valor = 150) or 
    (a2.nombre = 'ancho' and a2.valor = 300)

The result would be obtained in rows with the attributes one below the other for each article. If you need it transposed, you can take it to excel and use a dynamic table. Greetings.

NEW RESPONSE If you need to meet both conditions with different attributes, you use subqueries:

SELECT a.Id, a.descripcion, a.color, a2.nombre, a2.valor  
FROM articulos AS a
INNER JOIN atributos AS a2
    ON (a.Id = a2.Id_art)
WHERE ( SELECT COUNT(*) 
        FROM atributos AS a3
        WHERE a.Id = a3.Id_art AND 
            a3.nombre = 'alto' AND 
            a3.valor = 150) >=1  AND 
      ( SELECT COUNT(*) 
        FROM atributos AS a3
        WHERE a.Id = a3.Id_art AND 
            a3.nombre = 'ancho' and 
           a3.valor = 300) >=1

Subqueries count the records where your conditions are met in the attributes, if they give greater than or equal to 1 in each of them, it fulfills the condition you are looking for.

You need a Double Join