Question

此查询应该为我提供已取消的约会（post_appt_status_id = 3）并且尚未重新预订。

SELECT appointments.id, concat_ws(' ', contacts.first_name, contacts.last_name) AS contact_name, contacts.id, appointments.start AS appt_date
 FROM
 appointments appts2
 LEFT JOIN contacts ON contacts.id = appointments.contact_id
 WHERE marketing_event_id ='740' AND appointments.company_id = '1' 
 AND appointments.post_appt_status_id = '3'
 AND contacts.id NOT IN (SELECT contact_id FROM appointments WHERE appointments.start > appt_date)
 GROUP BY contacts.id

问题在于子选择。我无法传递appt_date值以使其工作。我得到一个错误，它是一个未知的列。

Answer 1

正如您所见，您不能使用这样的别名。相反，您可以完全限定列名称并引用外部查询中的表：

SELECT     appointments.id, 
           concat_ws(' ', contacts.first_name, contacts.last_name) AS 
               contact_name,
           contacts.id, 
           appointments.start AS appt_date
 FROM      appointments appts2
 LEFT JOIN contacts ON contacts.id = appointments.contact_id
 WHERE     marketing_event_id ='740' AND 
           appointments.company_id = '1' AND 
           appointments.post_appt_status_id = '3' AND
           contacts.id NOT IN (SELECT contact_id 
                               FROM   appointments
                               WHERE  appointments.start > appts2.start -- Here!
                              )
 GROUP BY contacts.id

Answer 2

您必须使用别名appts2：

SELECT appointments.id, concat_ws(' ', contacts.first_name, contacts.last_name) AS contact_name, contacts.id, appointments.start AS appt_date
 FROM
 appointments appts2
 LEFT JOIN contacts ON contacts.id = appts2.contact_id
 WHERE marketing_event_id ='740' AND appts2.company_id = '1' 
 AND appts2.post_appt_status_id = '3'
 AND contacts.id NOT IN (SELECT contact_id FROM appointments WHERE appointments.start > appts2.appt_date)
 GROUP BY contacts.id

Mysql查询：什么不在

2 个答案: