在结果列中联接表时遇到问题。我有一个工作查询，它使用union组合不同的表，但是当我扩展另一个表时，我得到一个错误，说“使用的select语句有不同的列数”
我的问题是：

(SELECT
    IDNumber,
    CONCAT(LastName, ', ', FirstName, ' ', Middle) as Name,
    CONCAT(EmDesignation, ', ', Department) as Information,
    Image,
    v.PlateNo as PlateNumber
FROM
    tblemployee as e, tblvehicle as v
WHERE 
    v.RFIDNo LIKE '6424823943'
AND
    e.RFIDNo LIKE '6424823943')
UNION
(SELECT 
    IDNumber,
    CONCAT(LastName, ', ', FirstName, ' ', Middle) as Name,
    CONCAT(Course, ', ', Year) as Information,
    Image,
    v.PlateNo as PlateNumber
FROM
    tblstudents as s, tblvehicle as v
WHERE
    v.RFIDNo LIKE '6424823943'
AND
    s.RFIDNo LIKE '6424823943')

我对此有意见。上面的继续查询

UNION
(SELECT
    Barrier
FROM 
    tblinformation as inf
WHERE
    inf.RFIDNo IN (6424823943)
ORDER BY 
    AttendanceNo DESC LIMIT 1)