参考：

Question

我不明白为什么mysql说where子句中有未知的列。如果我删除别名并只使用log_archive.date，那么它可以正常工作。

这是sql：

SELECT DISTINCT(log_archive.msisdn) AS msisdn,
       DATE(log_archive.date) AS actionDate,
       users.activation_date

        FROM log_archive 

        INNER JOIN users on log_archive.msisdn = users.msisdn

        WHERE log_archive.action = 'pokrenuta aplikacija' AND
              actionDate BETWEEN ':start_date' AND ':end_date'

        ORDER BY actionDate DESC

以下是错误消息：

'where子句'
中的未知列'actionDate'

MySQL版本是5.1.36。

Answer 1

列别名不能用于WHERE子句。

参考：

http://dev.mysql.com/doc/refman/5.7/en/problems-with-alias.html

标准SQL不允许在WHERE子句中引用列别名。强制执行此限制是因为WHERE子句是评估后，列值可能尚未确定。对于例如，以下查询是非法的：

Answer 2

因为actionDate不是列的别名，actionDate是函数DATE的结果的别名

如果更改sql如下，它仍然有效，所以问题不是别名，你必须使用where子句中的确切列。

SELECT DISTINCT(log_archive.msisdn) AS msisdn,
       log_archive.date AS actionDate,
       users.activation_date
FROM log_archive 
INNER JOIN users on log_archive.msisdn = users.msisdn
WHERE log_archive.action = 'pokrenuta aplikacija' AND
     DATE(actionDate) BETWEEN ':start_date' AND ':end_date'
ORDER BY actionDate DESC

Answer 3

列别名不能在WHERE子句中使用。您可以将该逻辑移动到派生表中：

SELECT DISTINCT msisdn, actionDate, activation_date
FROM
(
  SELECT log_archive.msisdn AS msisdn,
         DATE(log_archive.date) AS actionDate,
         users.activation_date AS activation_date
  FROM log_archive 
      INNER JOIN users on log_archive.msisdn = users.msisdn
  WHERE log_archive.action = 'pokrenuta aplikacija'
) dt
WHERE actionDate BETWEEN ':start_date' AND ':end_date'
ORDER BY actionDate DESC

或者，仅限MySQL用户，在HAVING子句中具有列别名条件。

或者只是将DATE(log_archive.date) BETWEEN ...放在WHERE子句中。

Answer 4

列别名不能在WHERE子句中使用。而是可以使用Having子句。

SELECT DISTINCT
    (log_archive.msisdn) AS msisdn,
    DATE(log_archive.date) AS actionDate,
    users.activation_date
FROM
    log_archive
        INNER JOIN
    users ON log_archive.msisdn = users.msisdn
WHERE
    log_archive.action = 'pokrenuta aplikacija'
having actionDate BETWEEN ':start_date' AND ':end_date'
ORDER BY actionDate DESC

您也可以通过

来完成

SELECT DISTINCT
    (log_archive.msisdn) AS msisdn,
    DATE(log_archive.date) AS actionDate,
    users.activation_date
FROM
    log_archive
        INNER JOIN
    users ON log_archive.msisdn = users.msisdn
WHERE
    log_archive.action = 'pokrenuta aplikacija' AND DATE(log_archive.date) BETWEEN ':start_date' AND ':end_date'
ORDER BY actionDate DESC

Mysql别名列在where子句中未知

4 个答案:

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