Question

I have this table:

id       characteristic      value
 1          color            blue
 1          shape            rectangle
 2          color            green
 2          shape            triangle

I need to select the id’s based on color and shape, for instance, I want to select the ids which the color is blue and the shape is rectangle (it would return only the value 1).

The primary key is composite (id + characteristic) so no id will have more than one value for a characteristic.

Also, there is the possibility to have more or less characteristics.

Could anyone help me on this one?

Best regards

Answer 1

SELECT  id
  FROM  MyTable t
        JOIN MyTable t2 ON t.id = t2.id
 WHERE  t.characteristic  = 'color' AND t.value ='blue'
   AND  t2.characteristic = 'shape' AND t2.value='rectangle' --just fixed the t1 to t2