MySQL与Count的比较

Question

我正在尝试更新活动字段，并根据向客户发送的产品数量进行设置。但它没有按预期工作。我有一些记录，其中issueShipped大于totalIssues但isActive未被设置为false。

UPDATE xatm.subscriptions a, 
       (SELECT idSubscription, COUNT(idProduct) issueShipped 
        FROM xatm.subscriptionshipments 
        group by idSubscription) b 
SET a.isActive = (a.totalIssues > b.issueShipped)
WHERE a.idsubscriptions = b.idSubscription
AND a.isComp = 0 AND a.isReoccurring = 0;

Answer 1

我实际上认为您当前的查询应该有效，但无论如何，您可以尝试的替代方案是更新连接：

UPDATE xatm.subscriptions a
INNER JOIN
(
    SELECT idSubscription, COUNT(idProduct) issueShipped 
    FROM xatm.subscriptionshipments 
    GROUP BY idSubscription
) b
    ON a.idsubscriptions = b.idSubscription
SET a.isActive = (a.totalIssues > b.issueShipped)
WHERE 
    a.isComp = 0 AND
    a.isReoccurring = 0;