shorting mysql query mit mehr Leistung

Question

Wie kann ich diese Abfrage verkürzen?

SET sql_mode = ''; 
SELECT t1.`id_number`,t1.`parents_id_number`,t1.`student_first_name`, 
    SUM(t1.`degree_value`) AS `values`, 
    (SELECT `user_key` 
     FROM data_users.account_info t2 
     WHERE t1.id_number = t2.id_number AND t1.parents_id_number = t2.parents_id_number 
     LIMIT 1) AS `user_key`, 
    (SELECT `first_name` 
     FROM data_users.account_info t2 
     WHERE t1.id_number = t2.id_number AND t1.parents_id_number = t2.parents_id_number 
     LIMIT 1) AS `first_name`, 
    (SELECT `last_name` 
     FROM data_users.account_info t2 
     WHERE t1.id_number = t2.id_number AND t1.parents_id_number = t2.parents_id_number 
     LIMIT 1) AS `last_name`, 
    (SELECT `about_me` 
     FROM data_users.account_info t2 
     WHERE t1.id_number = t2.id_number AND t1.parents_id_number = t2.parents_id_number 
     LIMIT 1) AS `about_me` 
FROM `1479213957519` t1  
WHERE t1.year_half = '1' 
GROUP BY t1.`perfix` 
ORDER BY `Values` DESC 
LIMIT 6 

Answer 1

Verwenden Sie eine Verknüpfung anstelle von korrelierten Unterabfragen.

SELECT t1.`id_number`,t1.`parents_id_number`,t1.`student_first_name`, 
     SUM(t1.`degree_value`) AS `values`, 
     t2.user_key, t2.first_name, t2.last_name, t2.about_me 
FROM `1479213957519` t1 
JOIN (SELECT * 
     FROM data_users.account_info 
     GROUP BY id_number, parents_id_number) t2 
    ON t1.id_number = t2.id_number AND t1.parents_id_number = t2.parents_id_number 
WHERE t1.year_half = '1' 
GROUP BY t1.`perfix` 
ORDER BY `Values` DESC 
LIMIT 6 

Wenn id_number und parents_id_number eine Zeile eindeutig in account_info identifiziert, brauchen Sie nicht die Unterabfrage, können Sie einfach mit dem Tisch selbst verbinden.

SELECT t1.`id_number`,t1.`parents_id_number`,t1.`student_first_name`, 
     SUM(t1.`degree_value`) AS `values`, 
     t2.user_key, t2.first_name, t2.last_name, t2.about_me 
FROM `1479213957519` t1 
JOIN data_users.account_info t2 
    ON t1.id_number = t2.id_number AND t1.parents_id_number = t2.parents_id_number 
WHERE t1.year_half = '1' 
GROUP BY t1.`perfix` 
ORDER BY `Values` DESC 
LIMIT 6