I have two tables, employees and unionMembers. The people in unionMembers are a small subset of the people in employees. I want to do a SELECT query using a LEFT JOIN like so:
SELECT wage, unionDues FROM employees LEFT JOIN unionMembers ON employees.ID = unionMembers.ID WHERE employees.ID = 'ID001';
Does it matter if I do
ON employees.ID = unionMembers.ID or reverse the order and do
ON unionMembers.ID = employees.ID?
Let's say I have 100 employees and 5 of them are union members. When doing the LEFT JOIN, ideally it would have to do 5 comparisons instead of a 100. Would the order of the equality test make any difference?