收到错误：1241（21000）：操作数应包含1列？

Question

SELECT CONCAT(Staff.fName, ' ', Staff.lName) AS 'Name', Staff.jobRole AS 'Job', Volunteer.firstAid AS 'First Aid?',(Volunteer.fName, ' ',  Volunteer.lName) AS 'Name', Staff.contactNo AS 'Phone number', Volunteer.contactNo AS 'Phone number', Event.eventID, Event.eventName AS 'Event Name', Event.startDateTime AS 'Start Date/Time'
    FROM EventStaff
        JOIN Staff
             ON Staff.staffID = EventStaff.staffID
        JOIN Event  
             ON Event.eventID = EventStaff.eventID
        JOIN EventVolunteer
             ON EventVolunteer.eventID = Event.eventID
        JOIN Volunteer
             ON EventVolunteer.volunteerID = Volunteer.volunteerID
ORDER BY Event.startDateTime;

So I am trying to make a query for my table that involves 3 5 different tables (2 compounds) these are: Staff, Event, Volunteer, EventStaff and EventVolunteer.

The query I am trying to answer is:

"What staff and volunteers are attending what event and what are their job roles. Include if they are First aid qualified. Also provide first name and last name and their contact number and start date/time of the event."

This error I keep getting I've looked around online but cant seem to resolve it.

Answer 1

There is a CONCAT missing. You also can use CONCAT_WS(' ', field1,field2)

SELECT 
CONCAT(Staff.fName, ' ', 
Staff.lName) AS 'Name', 
Staff.jobRole AS 'Job', 
Volunteer.firstAid AS 'First Aid?',
CONCAT(Volunteer.fName, ' ',  
Volunteer.lName) AS 'Name', 
Staff.contactNo AS 'Phone number', Volunteer.contactNo AS 'Phone number', Event.eventID, Event.eventName AS 'Event Name', Event.startDateTime AS 'Start Date/Time'
    FROM EventStaff
        JOIN Staff
             ON Staff.staffID = EventStaff.staffID
        JOIN Event  
             ON Event.eventID = EventStaff.eventID
        JOIN EventVolunteer
             ON EventVolunteer.eventID = Event.eventID
        JOIN Volunteer
             ON EventVolunteer.volunteerID = Volunteer.volunteerID
ORDER BY Event.startDateTime;

Answer 2

You could do something like this. Just make sure that the 2 select stamements have an equal number of columns. Hope this can help you further.

SELECT 'Staff Member' AS N, Staff.fName + ' ' + Staff.lName AS Name, Event.Id, Event.eventName, Event.startDateTime
FROM Staff 
  INNER JOIN EventStaff
    ON Staff.staffId = EventStaff.staffId
  INNER JOIN Event
    ON Event.eventId = EventStaff.eventId
UNION ALL
SELECT 'Volunteer' AS N, Volunteer.fName + ' ' + Volunteer.lName AS Name, Event.Id, Event.eventName, Event.startDateTime
FROM Volunteer 
  INNER JOIN EventVolunteer
    ON Volunteer.staffId = EventVolunteer.staffId
  INNER JOIN Event
    ON Event.eventId = EventVolunteer.eventId