Ano platí.

Nakonec jsem na to ovšem namísto inteligence použil brůtalní sílu:


SELECT *
FROM (

SELECT p.products_image, d.products_name, p.products_model, d.products_id, d.products_description, p.abra_sc_id, '0' as kategorie,
CASE nz.nl_id
WHEN 31
THEN 'checked'
ELSE 'Null'
END AS checkbox_checked,
CASE nz.v_akci
WHEN 31
THEN 'checked'
ELSE 'Null'
END AS v_akci
FROM products p
INNER JOIN products_description d ON d.products_id = p.products_id
LEFT JOIN newsletters_zbozi nz ON nz.id_zbozi = p.products_id
AND nz.nl_id =31
) AS zbozi
WHERE checkbox_checked = 'checked'
UNION
SELECT *
FROM (

SELECT p.products_image, d.products_name, p.products_model, d.products_id, d.products_description, p.abra_sc_id, '1' as kategorie,
CASE nz.nl_id
WHEN 31
THEN 'checked'
ELSE 'Null'
END AS checkbox_checked,
CASE nz.v_akci
WHEN 31
THEN 'checked'
ELSE 'Null'
END AS v_akci
FROM products p
INNER JOIN products_description d ON d.products_id = p.products_id
LEFT JOIN newsletters_zbozi_skupiny nz ON nz.id_zbozi = p.products_id
AND nz.nl_id =31
) AS zbozi
WHERE checkbox_checked = 'checked'



Pomocí UNION.


Děkuji za asistenci, ještě se vrátím