Optimize slow mysql query

Question

I'm using the following query to select a list of users, but the query is very slow. Could someone explain to me how I can optimize this query?

Thanks in advance.

Greetings Fred.

    SELECT 

    crmUser.userID, 
    crmUser.userFirstName, 
    crmUser.userLastName, 
    crmUser.userSekse, 
    TIMESTAMPDIFF(YEAR, crmUser.userBirthday,NOW()) AS age, 
    crmUser.userTelephone, 
    crmUser.userEmail,                          
    crmUser.userCity, 
    crmUser.userPlaceOfBirth, 
    content_City.province, 

    MAX(DATE_FORMAT(crmConnect.connectStamp, '%Y-%m-%d')) AS laatstGesolliciteerd,
    TIMESTAMPDIFF(WEEK, MAX(crmConnect.connectStamp),NOW()) AS laatsteActiviteit,
    COUNT(DISTINCT crmConnect.connectParent) AS Jobs,                               
    SUM(IF(crmConnect.connectExtra = 'interest', 1, 0)) AS Interest,
    SUM(IF(crmConnect.connectExtra = 'select', 1, 0)) AS Prospect,
    SUM(IF(crmConnect.connectExtra = 'winner', 1, 0)) AS Winner

FROM crmUser 
LEFT JOIN content_City ON (content_City.cityName = crmUser.userCity)
LEFT JOIN crmConnect ON (crmConnect.connectChild = crmUser.userID) 
LEFT JOIN crmJob ON (crmJob.jobID = crmConnect.connectParent) 

WHERE 

    crmUser.userID NOT IN (111, 222, 333, 444) AND
    crmUser.userActive = 1 AND 
    crmUser.userExtra = 0 AND

    crmConnect.connectType = 'user' AND 
    crmConnect.connectStamp != '0000-00-00 00:00:00' 

GROUP BY userID 

ORDER BY userID ASC

LIMIT 3000

Answer 1

You can eliminate the join to the jobs (from what I can tell). You can also simplify some of the logic, although this won't have much impact on performance. With this query:

SELECT u.userID, u.userFirstName, u.userLastName, u.userSekse, 
       TIMESTAMPDIFF(YEAR, u.userBirthday, NOW()) AS age, 
       u.userTelephone, u.userEmail, u.userCity, u.userPlaceOfBirth, 
       cc.province, 
       MAX(c.connectStamp) AS laatstGesolliciteerd,
       TIMESTAMPDIFF(WEEK, MAX(c.connectStamp), NOW()) AS laatsteActiviteit,
       COUNT(DISTINCT c.connectParent) AS Jobs,                               
       SUM(c.connectExtra = 'interest') AS Interest,
       SUM(c.connectExtra = 'select') AS Prospect,
       SUM(c.connectExtra = 'winner') AS Winner
FROM crmUser u LEFT JOIN
     content_City cc
     ON cc.cityName = u.userCity LEFT JOIN
     crmConnect c
     ON c.connectChild = u.userID
WHERE u.userID NOT IN (111, 222, 333, 444) AND
      u.userActive = 1 AND 
      u.userExtra = 0 AND
      c.connectType = 'user' AND 
      c.connectStamp <> '0000-00-00 00:00:00' 
GROUP BY u.userID ;

You want indexes. I would suggest crmuser(userActive, userExtra, UserID) , content_City(cityName, province) , and crmConnect(connectChild, connectType, connectStamp, connectParent, connectExtra) .