prueba esto:
Para obtener la fecha de inicio del trimestre actual, use esto:
SELECT MAKEDATE(YEAR(CURDATE()), 1) + INTERVAL QUARTER(CURDATE()) QUARTER
- INTERVAL 1 QUARTER
Entonces su consulta sería:
SELECT
QUARTER(r.callDate) AS quar,
YEAR(r.callDate) AS ryear,
MAKEDATE(YEAR(r.callDate), 1) + INTERVAL QUARTER(r.callDate) QUARTER -
INTERVAL 1 QUARTER AS scoreDateStart,
(SELECT DATE (DATE_SUB( DATE_ADD( CONCAT( YEAR( r.callDate ), '-01-01'),
INTERVAL QUARTER(r.callDate) QUARTER ), INTERVAL 1 DAY))) AS scoreDateEnd,
group_concat(DISTINCT(r.resultId) separator ', ') AS resultIds
FROM results AS r
GROUP BY quar, ryear
ORDER BY quar;