Question

我希望有人可以解释为什么这个查询需要花费近3分钟来执行，结果只有18行。

添加到WHERE子句以显示最多2个月前的结果时会出现问题。

执行以下查询大约需要2分40秒：

SELECT carts.id AS id, carts.order_id, carts.product_id, users.title, users.first_name, users.last_name, details.date_time, details.status 
    FROM orders_carts AS carts 
        LEFT JOIN orders_details AS details 
        ON carts.order_id = details.order_id

        LEFT JOIN orders_users AS users 
        ON users.order_id = details.order_id 

        WHERE carts.product_id = '11698'
        AND details.date_time >= now()-INTERVAL 2 month
        ORDER BY id DESC;

然而，此查询在大约1.5秒内执行：

SELECT carts.id AS id, carts.order_id, carts.product_id, users.title, users.first_name, users.last_name, details.date_time, details.status 
    FROM orders_carts AS carts 
        LEFT JOIN orders_details AS details 
        ON carts.order_id = details.order_id

        LEFT JOIN orders_users AS users 
        ON users.order_id = details.order_id 

        WHERE carts.product_id = '11698'
        ORDER BY id DESC

唯一添加的是AND details.date_time >= now()-INTERVAL 2 month，我不知道为什么它会导致滞后。有人可以帮忙吗？

SQL查询需要近3分钟？

0 个答案: