Question

如果查询条件允许，我有以下查询从wpr_subscribers中获取行。

SELECT subscribers.* FROM wpr_subscribers subscribers, wpr_followup_subscriptions subscriptions WHERE 
            subscribers.id=subscriptions.sid AND
            subscribers.active=1 AND
            subscribers.confirmed=1 AND
            subscriptions.type='autoresponder' AND
            subscriptions.eid=$autoresponder_id AND 
            subscriptions.sequence = -2 OR
            CEIL((subscriptions.last_date-subscriptions.doc)/86400) >= $message_index

查询返回每行中的两行。我该如何解决这个问题？

Answer 1

SELECT DISTINCT subscribers.* FROM wpr_subscribers subscribers, wpr_followup_subscriptions
subscriptions WHERE 
        subscribers.id=subscriptions.sid AND
        subscribers.active=1 AND
        subscribers.confirmed=1 AND
        subscriptions.type='autoresponder' AND
        subscriptions.eid=$autoresponder_id AND 
        subscriptions.sequence = -2 OR
        CEIL((subscriptions.last_date-subscriptions.doc)/86400) >= $message_index

DISTINCT关键字可以帮助您仅返回表中的唯一（不同）行。您确定查询中AND和OR的逻辑以及您现在收到的唯一数据确实是正确的。仅对于信息，AND运算符优先于OR，但是您可以使用括号覆盖它。

Answer 2

可能是您的OR声明

        subscriptions.sequence = -2 OR
        CEIL((subscriptions.last_date-subscriptions.doc)/86400) >= $message_index

无论OR的范围是什么

，都应将其括在括号中

如何解决这个SQL查询？

2 个答案: