I think you can for sure use more than one condition to join the tables. In any case, if just one boolean expression was permitted, I think you should only need to place all conditions inside parenthesis, because at the end, all of them will evaluate to one single 'true' or 'false'. By definition, JOIN conditions are part of the FROM clause, not part of the WHERE clause, so the resultant join table will contain all records which satisfy both conditions, but since the second condition in your example is comparing a field from table b to a specific value, which has nothing to do with the other joined table, I think the result would be the same as if you put that condition in the where clause (although the execution plan could be different), and I would prefer the latter for better readability. -----------------------------------------------

I think you can for sure use more than one condition to join the tables. In any case, if just one boolean expression was permitted, I think you should only need to place all conditions inside parenthesis, because at the end, all of them will evaluate to one single 'true' or 'false'. By definition, JOIN conditions are part of the FROM clause, not part of the WHERE clause, so the resultant join table will contain all records which satisfy both conditions, but since the second condition in your example is comparing a field from table b to a specific value, which has nothing to do with the other joined table, I think the result would be the same as if you put that condition in the where clause (although the execution plan could be different), and I would prefer the latter for better readability. -----------------------------------------------