Как оптимизировать подзапрос - PullRequest
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Как оптимизировать подзапрос

2 голосов
/ 21 мая 2019

У меня есть запрос с несколькими подзапросами, чтобы подсчитать, сколько пользователей, вовлеченных в определенную транзакцию, зависит от статуса. 

SELECT * FROM (
    SELECT
    DATE(changes.created_at) AS `date`,
    SUM(IF(changes.status = 15, 1, 0)) AS installed_daily,
    SUM(IF(changes.status = 3, 1, 0)) AS port_reserved,
    (
      SELECT COUNT(DISTINCT created_by) FROM applicant_state_changes
      WHERE DATE(created_at) = DATE(changes.created_at) AND status = 3
    ) AS user_port_reserved,
    SUM(IF(changes.status = 5, 1, 0)) AS document_validated,
    (
      SELECT COUNT(DISTINCT created_by) FROM applicant_state_changes
      WHERE DATE(created_at) = DATE(changes.created_at) AND status = 5
    ) AS user_document_validated,
    SUM(IF(changes.status = 7, 1, 0)) AS account_created,
    (
      SELECT COUNT(DISTINCT created_by) FROM applicant_state_changes
      WHERE DATE(created_at) = DATE(changes.created_at) AND status = 7
    ) AS user_account_created,
    SUM(IF(changes.status = 11, 1, 0)) AS jo_created,
    (
      SELECT COUNT(DISTINCT created_by) FROM applicant_state_changes
      WHERE DATE(created_at) = DATE(changes.created_at) AND status = 11
    ) AS user_jo_created
    FROM applicant_state_changes AS changes
    GROUP BY DATE(changes.created_at)
    LIMIT 100 OFFSET 0
) a
ORDER BY date ASC;

Это занимает около 130 секунд.Без подзапросов мой запрос занимает всего 0,5 секунды.

1 Ответ

4 голосов
/ 21 мая 2019

Вы можете использовать условное агрегирование, используя случай, когда выражение 

 SELECT
    DATE(changes.created_at) AS `date`,
    SUM(IF(changes.status = 15, 1, 0)) AS installed_daily,
    SUM(IF(changes.status = 3, 1, 0)) AS port_reserved,
    count(distinct case when status = 3 then created_by end) as user_port_reserved
    ,
    SUM(IF(changes.status = 5, 1, 0)) AS document_validated,
    count(distinct case when status = 5 then created_by  end) AS user_document_validated,
    SUM(IF(changes.status = 7, 1, 0)) AS account_created,
    count(distinct case when status = 7 then 1 end) AS user_account_created,
    SUM(IF(changes.status = 11, 1, 0)) AS jo_created,
    count(distinct case when status = 11 then created_by  end) AS user_jo_created
    FROM applicant_state_changes AS changes where 
    GROUP BY DATE(changes.created_at)
    LIMIT 100 OFFSET 0
...