我有 3 个表,我试图从中返回一个列,这让我哭泣为什么它不起作用:
$projectId = 54971033
$id = 53189015
SELECT
iR.author,
i.dateCreated,
i.lastModified,
i.value,
u.username
FROM
informationRelationships iR
INNER JOIN
information i ON
iR.linkId = i.id
INNER JOIN
users u ON
iR.author = u.id
WHERE
iR.contactRef = '$id' AND
iR.projectRef = '$projectId' AND
iR.type = 'Project'
知道为什么它什么都不返回吗?
最佳答案
author
为零,因此请尝试使用 LEFT JOIN
:
SELECT
iR.author,
i.dateCreated,
i.lastModified,
i.value,
u.username
FROM
informationRelationships iR
LEFT JOIN
information i ON
iR.linkId = i.id
LEFT JOIN
users u ON
iR.author = u.id
WHERE
iR.contactRef = '$id' AND
iR.projectRef = '$projectId' AND
iR.type = 'Project'
关于php - 使用此内部连接获取数据时遇到问题 (MYSQL/PHP),我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/17025894/