Mysql查询优化耗时30多秒

Question

嗨朋友们可以请任何人帮我优化这个查询，它需要30多秒。 任何建议都热烈欢迎。

查询：

SELECT 
    CONCAT(CCD.CONTACT_FIRST_NAME, ' ', CCD.CONTACT_LAST_NAME) AS NAME,
    A.EMAIL_IDS,
    CCD.UNSUBSCRIBE,
    IFNULL(CSL.LOG_DATE, '') AS LOG_DATE,
    CSL.IP_ADDRESS,
    IF(CSL.BROWSER IS NULL, '', CSL.BROWSER) AS BROWSER,
    (CASE
        WHEN (UNSUBSCRIBE = 0 OR UNSUBSCRIBE IS NULL) THEN 'Opted In'
        ELSE (CASE
            WHEN (UNSUBSCRIBE = 1) THEN 'Opted Out'
            ELSE (CASE
                WHEN
                    ((UNSUBSCRIBE = 2 OR UNSUBSCRIBE = 3)
                        AND CCD.CONTACT_ID NOT IN (SELECT 
                            CONTACT_ID
                        FROM
                            CM_SUBSCRIPTION_MAIL_DATA
                        WHERE
                            IS_MAIL_SENT = 'Y'))
                THEN
                    'Opt-In Request not Sent'
                ELSE 'Opt-In Pending'
            END)
        END)
    END) AS CURR_SUB,
    (CASE
        WHEN (SUBSCRIBE_FROM = 0) THEN 'Opted In'
        ELSE (CASE
            WHEN (SUBSCRIBE_FROM = 1) THEN 'Opted Out'
            ELSE (CASE
                WHEN (SUBSCRIBE_FROM = 2 OR SUBSCRIBE_FROM = 3) THEN 'Opt-In Pending'
                ELSE ''
            END)
        END)
    END) AS SUB_FROM,
    SUBSCRIBE_FROM,
    (CASE
        WHEN (SUBSCRIBE_TO = 0) THEN 'Opted In'
        ELSE (CASE
            WHEN (SUBSCRIBE_TO = 1) THEN 'Opted Out'
            ELSE (CASE
                WHEN (SUBSCRIBE_TO = 2 OR SUBSCRIBE_TO = 3) THEN 'Opt-In Pending'
                ELSE ''
            END)
        END)
    END) AS SUB_TO,
    SUBSCRIBE_TO
FROM
    CM_CONTACT_DETAILS CCD
        LEFT JOIN
    ADDRESS A ON CCD.CONTACT_ID = A.FOREIGN_ID
        LEFT JOIN
    CM_SUBSCRIPTION_LOGS CSL ON CSL.CONTACT_ID = CCD.CONTACT_ID
WHERE
    1 = 1
GROUP BY CSL.LOG_DATE , CCD.CONTACT_ID
ORDER BY NAME DESC , LOG_DATE DESC
LIMIT 0 , 20

Answer 1

您的案例/何时可以简化，但我相信您查询的杀手是未发送您的选择加入请求的相关 NOT IN SELECT 子句。

我已将您的查询更改为根据联系人和“Y”的邮寄状态对您的邮寄表进行左连接。因此，这简化了您的案例，只需检查邮件表联系人 ID 的 IS NULL。

您不能在性能方面做太多事情，因为您的 Group by 是由不同表中的列组成的，不会利用任何索引优化，那么所有按名称排序的东西都会使它成为一个问题......但是每次对左连接执行的每个字段的相关子查询应该有帮助。

SELECT 
      CONCAT(CCD.CONTACT_FIRST_NAME, ' ', CCD.CONTACT_LAST_NAME) AS NAME,
      A.EMAIL_IDS,
      CCD.UNSUBSCRIBE,
      IFNULL(CSL.LOG_DATE, '') AS LOG_DATE,
      CSL.IP_ADDRESS,
      IF(CSL.BROWSER IS NULL, '', CSL.BROWSER) AS BROWSER,
      CASE WHEN UNSUBSCRIBE = 0 OR UNSUBSCRIBE IS NULL THEN 'Opted In'
           WHEN UNSUBSCRIBE = 1 THEN 'Opted Out'
           WHEN UNSUBSCRIBE IN (2,3) AND SMD.CONTACT_ID IS NULL THEN 'Opt-In Request not Sent'
           ELSE 'Opt-In Pending' END AS CURR_SUB,
      CASE WHEN SUBSCRIBE_FROM = 0 THEN 'Opted In'
           WHEN SUBSCRIBE_FROM = 1 THEN 'Opted Out'
           WHEN SUBSCRIBE_FROM = 2 OR SUBSCRIBE_FROM = 3 THEN 'Opt-In Pending'
           ELSE '' END AS SUB_FROM,
      SUBSCRIBE_FROM,
      CASE WHEN SUBSCRIBE_TO = 0 THEN 'Opted In'
           WHEN SUBSCRIBE_TO = 1 THEN 'Opted Out'
           WHEN SUBSCRIBE_TO = 2 OR SUBSCRIBE_TO = 3 THEN 'Opt-In Pending'
           ELSE '' END AS SUB_TO,
      SUBSCRIBE_TO
   FROM
      CM_CONTACT_DETAILS CCD
         LEFT JOIN ADDRESS A 
            ON CCD.CONTACT_ID = A.FOREIGN_ID
         LEFT JOIN CM_SUBSCRIPTION_LOGS CSL 
            ON CSL.CONTACT_ID = CCD.CONTACT_ID
         LEFT JOIN CM_SUBSCRIPTION_MAIL_DATA SMD
            ON CCD.CONTACT_ID = SMD.CONTACT_ID
            AND IS_MAIL_SENT = 'Y'
   WHERE
      1 = 1
   GROUP BY 
      CSL.LOG_DATE, 
      CCD.CONTACT_ID
   ORDER BY 
      NAME DESC, 
      LOG_DATE DESC
   LIMIT 
      0, 20