SELECT fn_chairs.bl_id,bl.name, 
SUM (fn_chairs.frs_score) as frs_score
FROM fn_chairs 
     INNER JOIN fl ON (fl.bl_id = fn_chairs.bl_id AND fl.fl_id = fn_chairs.fl_id)
     INNER JOIN bl on fn_chairs.bl_id = bl.bl_id
WHERE fl.is_active = 1
GROUP BY fn_chairs.bl_id

SELECT fn_chairs.bl_id,
       bl.name,
       SUM(fn_chairs.frs_score) AS frs_score
FROM   fn_chairs
       INNER JOIN fl
            ON  (fl.bl_id = fn_chairs.bl_id AND fl.fl_id = fn_chairs.fl_id)
       INNER JOIN bl
            ON  fn_chairs.bl_id = bl.bl_id
WHERE  fl.is_active = 1
GROUP BY
       fn_chairs.bl_id,
       bl.name

SELECT bl.bl_id,bl.name, ch.frs_score
FROM (SELECT c. bl_id,
SUM (fn_chairs.frs_score) as frs_score
FROM fn_chairs c 
INNER JOIN fl 
ON fl.bl_id = c.bl_id 
AND fl.fl_id = c.fl_id
WHERE fl.is_active = 1
GROUP BY c.bl_id)ch
INNER JOIN bl 
on ch.bl_id = bl.bl_id