SELECT `blends`.`id`,`blends`.`fileName`,`blends`.`questionLink`,`accesses`.`val`,
SUM(`accesses`.`ref` != `blends`.`questionLink` AND `accesses`.`ref` != '') AS invalidRefs, SUM(`accesses`.`ref` = `blends`.`questionLink`) AS validRefs,
SUM(`accesses`.`ref` != `blends`.`questionLink` AND `accesses`.`ref` != '') - SUM(`accesses`.`ref` = `blends`.`questionLink`) AS refGap
FROM `blends`
JOIN `accesses` ON `accesses`.`fileId` = `blends`.`id` AND `accesses`.`type` = 'view'
WHERE `blends`.`valid`= 0
GROUP BY `blends`.`id`