Php 缩短mysql查询以提高性能

如何缩短此查询

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

---

使用联接而不是相关子查询

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

如果

id\u number

和

parents\u id\u number

在

account\u info

中唯一标识一行，则不需要子查询，只需与表本身联接即可

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

---

使用联接而不是相关子查询

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

如果

id\u number

和

parents\u id\u number

在

account\u info

中唯一标识一行，则不需要子查询，只需与表本身联接即可

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

---

如果您有一个名为1479213957519的表，那么很可能是出现了严重错误，这是为post-dataWelcome@SaefMyth自动生成的表。我知道你是新加入社区的。在我看来，你的职位是不够的。我投票决定结束这个问题，因为社区认为它不属于主题（请参见指导原则），因为它不存在必须解决的问题，而是需要编码支持。这在SO中是严格禁止的。没有否决投票，因为您是第一次这样做。如果您有一个名为1479213957519的表，那么可能是出现了严重错误，这是为post dataWelcome@SaefMyth自动生成的表。我知道你是新加入社区的。在我看来，你的职位是不够的。我投票决定结束这个问题，因为社区认为它不属于主题（请参见指导原则），因为它不存在必须解决的问题，而是需要编码支持。这在SO中是严格禁止的。没有否决投票，因为你是新来的SO.perfcto man，，，第二个查询用了0.0014秒，第一个0.263秒，我的用了0.334秒，我需要学习更多的sql，，，谢谢dudeperfcto man，，，第二个查询用了0.0014秒，第一个0.263秒，我的用了0.334秒，我需要学习更多的sql，，，谢谢你，伙计