Query error:
Illegal mix of collations (latin1_swedish_ci,IMPLICIT) and (utf8mb4_unicode_ci,COERCIBLE) for operation '='

SQL query:
SELECT cat.cat_type, cat.cat_id, cat.cat_titel, cat.cat_url, prt.cat_url AS prt_url, prt.cat_id AS prt_id, prt.cat_titel AS prt_titel, tgd.usr_id AS tgd_id, tgd.usr_naam AS tgd_naam, gwd.usr_id AS gwd_id, gwd.usr_naam AS gwd_naam, vrt.* FROM leg_vertaling vrt INNER JOIN leg_categorie cat ON vrt.vrt_categorie = cat.cat_id LEFT JOIN leg_categorie prt ON cat.cat_parent = prt.cat_id LEFT JOIN leg_user tgd ON vrt.vrt_toegevoegd_id = tgd.usr_id LEFT JOIN leg_user gwd ON vrt.vrt_gewijzigd_id = gwd.usr_id WHERE vrt.vrt_url = 'brieven_uit_ad_atticum_xii_14_sb_251_����3' AND cat.cat_url = 'cicero'