Zen Cart v1.38a 订阅新闻发送的时候出现 SQL 错误

1104 The SELECT would examine more than MAX_JOIN_SIZE rows; check your WHERE and use SET SQL_BIG_SELECTS=1 or SET SQL_MAX_JOIN_SIZE=# if the SELECT is okay in: [SELECT DISTINCT c.customers_email_address as customers_email_address, c.customers_lastname as customers_lastname, c.customers_firstname as customers_firstname FROM customers c LEFT JOIN orders o ON c.customers_id=o.customers_id WHERE o.date_purchased IS NULL ]出现这个问题的 Zen Cart 版本为1.3.8a

需要解决这个问题,请将 Zen Cart 的版本升级到 v1.3.9, 采用推荐的方法进行升级。

或者执行下面的 SQL 脚本ALTER TABLE orders ADD INDEX customers_id (customers_id);需要在 orders.customers_id 中提供唯一索引,来提高处理的性能。在 v1.39 中已经进行更新了这个问题。