Come ottimizzare una query in mysql mentre si utilizza la clausola "group by"?

Question

Sto usando la seguente query che sta prendendo circa 52 secondi se raggruppati per 'supervisore' altrimenti si completa entro 2 o 3 secondi:

SELECT SQL_CALC_FOUND_ROWS MONTHNAME(o.sale_on) AS DATE, 
     SUM(od.current_status_id=1) AS sales, 
     IFNULL(SUM(CASE WHEN od.current_status_id=2 
        OR od.current_status_id=3 THEN 
        (SELECT SUM(amount) 
        FROM order_refund_chargeback 
        WHERE order_detail_id = od.order_detail_id) END),0) AS total_outflow, 
     IFNULL(
       (SELECT GROUP_CONCAT(CONCAT(user_first_name," ",user_last_name)) 
       FROM user_detail 
       WHERE user_id IN 
        (SELECT manager_id 
        FROM `user_org_map` 
        WHERE user_id = o.assigned_to)),"") AS supervisor, 
     IFNULL(mco.country_name,"") AS country 
FROM orders o 
RIGHT JOIN order_detail od 
    USING (order_id) 
LEFT JOIN user_detail ud 
    ON ud.user_id = o.assigned_to 
LEFT JOIN customer_detail cd 
    ON cd.customer_id= o.customer_id 
LEFT JOIN master_product mp 
    ON mp.product_id = od.product_id 
LEFT JOIN master_campaign mc 
    ON mc.campaign_id = cd.campaign_id 
LEFT JOIN master_country mco 
    ON mco.country_id = cd.country 
WHERE 1=1 
AND YEAR(o.sale_on) =2015 
GROUP BY supervisor 
ORDER BY supervisor ASC 
LIMIT 0, 12 

Qualsiasi suggerimento su come ottimizzare questo modo che la quantità di tempo può essere ridotto?

Answer 1

Non utilizzare la funzione data nella condizione where perché non è possibile usufruire della guida dell'indice. Invece del Condition YEAR(o.sale_on) =2015 uso:

o.sale_on BETWEEN '2015-01-01' AND '2015-12-31'.