SELECT
    c.id,
    c.socialName, 
    c.street AS postalAddress,
    IF (ios.taxAreaFk IS NOT NULL, CONCAT(cty.code, c.fi), c.fi) fi, 
    CONCAT(c.postcode, ' - ', c.city) postcodeCity
FROM vn.invoiceOut io
    JOIN vn.client c ON c.id = io.clientFk
    JOIN vn.country cty ON cty.id = c.countryFk
    LEFT JOIN vn.invoiceOutSerial ios ON ios.code = io.serial 
        AND ios.taxAreaFk = 'CEE'
    LEFT JOIN ticket t ON t.refFk = io.ref
WHERE t.refFk = ?