Ver originalSET GLOBAL group_concat_max_len=10000; //el valor 10000 es un ejemploSELECT *, YEAR(traveldate) as anio, MONTH(traveldate) as mes, DAY(traveldate) as dia, DATE_FORMAT(traveldate, '%M') as mes2, GROUP_CONCAT(DISTINCT DATE_FORMAT(traveldate, '<a href=\"link\">%d - %M</a>') ORDER BY traveldate SEPARATOR ' | ') as diaconcatFROM "tabla"WHERE "condiciones"GROUP BY anioORDER BY anio