我正在尝试连接 3 个表，但我的查询不断出错。我不确定我做错了什么。我一定是用我的语法做了一些不正确的事情，但我不太确定出了什么问题。
SELECT project_timecard_tasks.DateTime,
project_timecard_tasks.Total_Hours,
project_timecard_tasks.User_ID,
project_timecard_tasks.Task_ID,
project_timecard_tasks.Project_ID,
users.User_ID,
users.FirstName,
users.LastName,
tasks.id,
tasks.taskName
FROM project_timecard_tasks
JOIN project_timecard_tasks ON project_timecard_tasks.User_ID = users.User_ID
AND project_timecard_tasks.Task_ID = tasks.id
WHERE project_timecard_tasks.Project_ID = '$jobNumber'
你的JOIN陈述有点不稳定。 试试这个：
SELECT project_timecard_tasks.DateTime,
project_timecard_tasks.Total_Hours,
project_timecard_tasks.User_ID,
project_timecard_tasks.Task_ID,
project_timecard_tasks.Project_ID,
users.User_ID,
users.FirstName,
users.LastName,
tasks.id,
tasks.taskName
FROM project_timecard_tasks
JOIN users ON project_timecard_tasks.User_ID = users.User_ID
JOIN tasks ON project_timecard_tasks.Task_ID = tasks.id
WHERE project_timecard_tasks.Project_ID = '$jobNumber'
您正在从三个表中选择数据(project_timecard_tasks , users and tasks)但在from子句中您只提到了一个表。 您需要提及所有表名称，例如：
FROM project_timecard_tasks ,users, tasks
You JOIN 不正确。 您需要指定要连接的表。 将其替换为：
JOIN users ON project_timecard_tasks.User_ID = users.User_ID
JOIN tasks ON project_timecard_tasks.Task_ID = tasks.id
删除AND并在第二个连接语句中使用JOIN。
JOIN project_timecard_tasks ON project_timecard_tasks.User_ID = users.User_ID
JOIN project_timecard_tasks.Task_ID = tasks.id