Question

I have inherited a system which seemingly requires me to use a cursor or while loop.
Given the below tables, I would like to get the names of the attendees e.g

Bill
Bob
Jane
Jill

Attendees
SourceTable|SourceTableId
Boys |1
Boys |2
Girls |2
Girls |1

Boys
Id|FirstName
1 |Bill
2 |Bob

Girls
Id|FirstName
1 |Jill
2 |Jane

Note, the system doesn’t actually use Attendees,Boys & Girls but rather uses Contracts, Orders and other such entities etc but it was easier\simpler to represent in this form.
There may be loads more lookup tables than just “boy” and “girl” so

Is there anyway I can achieve this by not using cursors or other row based operations.

Answer 1

If I understand this query should work:

SELECT FirstName
  FROM Attendees
  join Boys on id = SourceTableId
 WHERE SourceTable = 'Boys'
union all
SELECT FirstName
  FROM Attendees
  join Girls on id = SourceTableId
 WHERE SourceTable = 'Girls'