Дублиране на заявка за MySQL Union/групиране по проблем

Не всичко е обединение -- в този случай това е обединение на подзаявките:

SELECT shpUserAdded AS userName, merCount, prdCount
FROM (SELECT shpUserAdded, count(*) AS shpCount FROM shops GROUP BY shpUserAdded ASC) AS s
JOIN (SELECT prdUserAdded, count(*) AS prdCount FROM products GROUP BY prdUserAdded ASC) AS p
ON (shpUserAdded = prdUserAdded);