Question

I have this query and it works great (not sure) about performance

SELECT ssp.product_id, p.price
FROM system_step_product AS ssp
JOIN product AS p ON p.product_id=ssp.product_id 
WHERE ssp.system_id = 14
AND ssp.step_number = (
  SELECT step_number
  FROM system_step_product
  WHERE system_id = '14'
  AND step_number > (
    SELECT step_number
    FROM system_step_product
    WHERE system_id = '14'
    AND product_id = '81'
    ORDER BY step_number ASC
    LIMIT 1
  )  
  ORDER BY step_number ASC
  LIMIT 1
)

If I have to go about it with this approach I will but i was wondering if anyone can think of a better way of executing this query

Answer 1

The two limit clauses make the join statement require the row_number() OVER () window function, which is not available in MySQL. And even that, would likely make your query less efficient than it currently is.