使用命名子查询删除

Question

我有一个 SQL 查询，如下所示：

DELETE
    price.*
FROM
    price
JOIN
    service
ON
    price.service_id = service.id
WHERE
    price.country_from_id NOT IN
        (SELECT
            country_id
        FROM
            carrier_zone_country
        JOIN
            carrier_zone
        ON
            carrier_zone_id = carrier_zone.id
        WHERE
            carrier_zone.carrier_service_id = service.carrier_service_id)
    OR
    price.country_to_id NOT IN
        (SELECT
            country_id
        FROM
            carrier_zone_country
        JOIN
            carrier_zone
        ON
            carrier_zone_id = carrier_zone.id
        WHERE
            carrier_zone.carrier_service_id = service.carrier_service_id)

我希望通过将子查询移动到 FROM 子句并为其命名来避免两次运行子查询。但是，这给了我语法错误。查看文档，我可以看到只有 SELECT FROM 子句可以在其中包含命名子查询。

首先我想知道为什么会这样？其次，我如何重写此 SQL 查询以避免执行相同的子查询两次。

Answer 1

做一个 NOT EXISTS 子查询，检查往返国家：

DELETE
    price.*
FROM
    price
JOIN
    service
ON
    price.service_id = service.id
WHERE
NOT EXIST(SELECT
            1
        FROM
            carrier_zone_country
        JOIN
            carrier_zone
        ON
            carrier_zone_id = carrier_zone.id
        WHERE country_id IN (price.country_from_id, price.country_to_id)
          AND carrier_zone.carrier_service_id = service.carrier_service_id))

使用命名子查询删除

DELETE FROM with named subquery

mysql

sql

select

subquery

sql-delete