subquery to list all distinct mgrid values

Question

This is the code I have. I am using TSQL Database

select lastname, firstname 
from HR.Employees 
where Employees.mgrid in 
   (select empid 
    from HR.Employees 
    where title = 'managers')

It only returns the column names. What am doing wrong?

Answer 1

0

If it is just returning the column headers, then that means it's an empty data set.

Break the query down to see where it is going wrong.

Does the sub-query select empid from HR.Employees where title = 'managers' return any rows?

If it does, is it returning valid values for mgrid that can be fed into the outer query?

Once we have answers for those, then we can talk about making this a JOIN query.

answered Jan 17 '11 at 10:33 AM

Kev Riley ♦♦
46.1k ● 39 ● 43 ● 69

may have to use sub query in order to satisfy homework question. May be simply a demonstration of how its implemented/used. You may spoil next chapter by moving on to a JOIN too soon. ++the butler did it++

Jan 18 '11 at 01:43 AM Fatherjack ♦♦

@Fatherjack LOL! Those pesky kids

Jan 18 '11 at 01:58 AM Kev Riley ♦♦

@Fatherjack - That's a problem I've had recently. I have been taking some SQL Server courses at Stockholm University. I had to take basic courses to be able to take on an optimization course and a Reporting Services course.

If found out during the basic courses that it's pretty hard to unlearn all the things you've learned, just to complete assignments on a basic enough level...

Jan 18 '11 at 03:36 AM Magnus Ahlkvist

@Magnus - that must be quite difficult. On the other hand, I'm sure it isn't nice for the professor if you know more than them

Jan 18 '11 at 04:05 AM WilliamD

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subquery to list all distinct mgrid values

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