sql - 无法在 SQL 查询的 WHERE 子句中使用字段

Question

我有这个问题:

select
    l.lead_id, l.lead_date_received, 
    TIMESTAMPDIFF(MINUTE, l.lead_date_received, NOW()) AS minutes, 
    s.admin_id, a.name, a.email
from
    leads l
        inner join sales_emails s on l.lead_id = s.lead_id
        inner join admin a on a.admin_id = s.admin_id
where
    not exists (select 1 from comments c where l.lead_id = c.lead_id)
order by
    minutes, l.lead_date_received desc

现在我想在 WHERE 子句中设置条件，例如 minutes > 30。但是，如您所见， minutes 只出现在 SELECT 子句中，而不出现在 FROM 子句或子查询中，这意味着我的条件像 minutes > 30 将不会在 WHERE 子句中被识别。

我该如何解决这个问题？

Answer 1

SELECT l.lead_id, l.lead_date_received, TIMESTAMPDIFF(MINUTE, l.lead_date_received, NOW()) AS minutes, s.admin_id,
       a.name, a.email
FROM   leads l
INNER  JOIN sales_emails s
ON     l.lead_id = s.lead_id
INNER  JOIN admin a
ON     a.admin_id = s.admin_id
WHERE  NOT EXISTS (SELECT 1 FROM comments c WHERE l.lead_id = c.lead_id)
AND    TIMESTAMPDIFF(MINUTE, l.lead_date_received, NOW()) > 30
ORDER  BY minutes, l.lead_date_received DESC

或添加另一个查询:

SELECT *
from
(
  SELECT l.lead_id, l.lead_date_received, TIMESTAMPDIFF(MINUTE, l.lead_date_received, NOW()) AS minutes, s.admin_id,
       a.name, a.email
FROM   leads l
INNER  JOIN sales_emails s
ON     l.lead_id = s.lead_id
INNER  JOIN admin a
ON     a.admin_id = s.admin_id
WHERE  NOT EXISTS (SELECT 1 FROM comments c WHERE l.lead_id = c.lead_id)
ORDER  BY minutes, l.lead_date_received DESC
)
Where minutes > 30