SELECT * FROM `tag` `t`
INNER JOIN `tag_meta` `tm` ON `t`.`tag_id` = `tm`.`tag_id`
INNER JOIN `tag_relationships` `tr` ON `tr`.`tag_id` = `t`.`tag_id`
WHERE `tm`.`type` = 'product_cat'
GROUP BY `t`.`name`  
ORDER BY `t`.`name`  ASC;