Question

我有一个查询，我使用InnoDB存储引擎。

我想优化它。执行需要太多时间。我的数据库中有500万个数据。现在需要250秒才能执行。

INSERT INTO dynamicgroups (adressid) 

    SELECT SQL_NO_CACHE DISTINCT(addressid) FROM (
        SELECT cluster_0.addressid FROM (
            SELECT DISTINCT addressid FROM (
                SELECT group_all.addressid FROM (
                    SELECT g.addressid FROM table2.635_emadresmgroups g 
                        INNER JOIN table2.emaildata f_0
                               ON f_0.addressid = g.addressid
                        WHERE  (f_0.birthday > date(DATE_SUB(NOW(),INTERVAL 18 MONTH))
                            AND f_0.birthday < CURDATE() )
                ) group_all
            ) AS groups

        ) AS cluster_0

        INNER JOIN(
            SELECT DISTINCT addressid FROM (
                SELECT group_all.addressid FROM (
                    SELECT g.addressid FROM table2.635_emadresmgroups g 
                        INNER JOIN table2.emaildata f_0
                               ON f_0.addressid = g.addressid
                        WHERE  (marriage_date = ''
                             OR marriage_date = '1900-01-01'
                             OR marriage_date = '0000-00-00' )
                ) group_all
            ) AS groups
        ) AS cluster_1 ON cluster_1.addressid = cluster_0.addressid

        INNER JOIN(
            SELECT DISTINCT addressid FROM (
                SELECT group_all.addressid FROM (
                    SELECT g.addressid FROM table2.635_emadresmgroups g 
                        INNER JOIN table2.emaildata f_0
                                ON f_0.addressid = g.addressid
                        WHERE  (f_0.city = '34' )
                ) group_all
            ) AS groups
        ) AS cluster_2 ON cluster_2.addressid = cluster_1.addressid 
    ) AS t

Answer 1

即使EXPLAIN运算符没有像其他运算符一样实现..我建议您将它用于查询。

之后，您可以分析EXPLAIN提供的结果，并决定应将哪些列编入索引。

有关详细信息，我建议您查看这些来源：

MySQL syntax: EXPLAIN

MySQL using: EXPLAIN

此外，最后2个选项看起来非常相似，也许您可以制作临时表或其中的视图，这样您就不必运行整个选择两次了？

Answer 2

您的查询似乎都是此查询的变体：

SELECT g.addressid
FROM table2.635_emadresmgroups g INNER JOIN
     table2.emaildata f_0
     ON f_0.addressid = g.addressid
WHERE  (f_0.birthday > date(DATE_SUB(NOW(),INTERVAL 18 MONTH)) AND f_0.birthday < CURDATE() )

我建议您使用group by和having：

来解决这个问题

SELECT g.addressid
FROM table2.635_emadresmgroups g INNER JOIN
     table2.emaildata f_0
     ON f_0.addressid = g.addressid
GROUP BY g.addressid
HAVING SUM(f_0.birthday > date(DATE_SUB(NOW(), INTERVAL 18 MONTH)) AND f_0.birthday < CURDATE() ) > 0 AND
       SUM(marriage_date = '' OR marriage_date = '1900-01-01'  OR marriage_date = '0000-00-00' ) > 0 AND
       SUM(f_0.city = '34' ) > 0;

根据数据量，group by之前的过滤也可以提供帮助：

SELECT g.addressid
FROM table2.635_emadresmgroups g INNER JOIN
     table2.emaildata f_0
     ON f_0.addressid = g.addressid
WHERE (f_0.birthday > date(DATE_SUB(NOW(), INTERVAL 18 MONTH)) AND f_0.birthday < CURDATE() ) OR
      (marriage_date = ''  OR marriage_date = '1900-01-01' OR marriage_date = '0000-00-00' ) OR
      (f_0.city = '34' )
GROUP BY g.addressid
HAVING SUM(f_0.birthday > date(DATE_SUB(NOW(), INTERVAL 18 MONTH)) AND f_0.birthday < CURDATE() ) > 0 AND
       SUM(marriage_date = '' OR marriage_date = '1900-01-01'  OR marriage_date = '0000-00-00' ) > 0 AND
       SUM(f_0.city = '34' ) > 0;

Answer 3

marriage_date - 将其设为NULLable并使用NULL而不是＆＃39;＆＃39;等等。这样可以避免效率低下OR和可能导致INDEX的可用性。

请提供SHOW CREATE TABLE，以便我们评估当前的索引。

你在运行什么版本？直到非常，最近这个构造非常效率低下：

FROM ( SELECT ... )
JOIN ( SELECT ... )

解决方法是将子查询放入tmp表并添加INDEX。

此可能会帮助您，因为您似乎正在使用JOINs进行过滤：将JOIN ( SELECT ... )变为WHERE EXISTS ( SELECT * ... )。

请用英文描述查询尝试做什么。

另一种方法，建立在Gordon建议的共同SELECT上：将常用的SELECT放入TEMPORARY表中;添加索引，然后从中查询。

如何优化具有2个不同内连接的Mysql查询？（InnoDB）

3 个答案:

如何优化具有2个不同内连接的Mysql查询？ （InnoDB）

3 个答案:

如何优化具有2个不同内连接的Mysql查询？（InnoDB）