Why select from multiple tables without join

Question

When joining tables one can traditionally use the SQL89 way of joining like

SELECT * FROM t1, t2 WHERE t1.id = t2.t1_id;

But since the SQL92 standard, we can now join using the JOIN syntax

SELECT * FROM t1 JOIN t2 on t1.id=t2.t1_id;

Is there any reason why someone would SELECT from multiple tables without joining? Now, I know people concatenate data using UNION, but that is not what I'm talking about.

Is the reason we add tables with commas in the FROM clause strictly for backwards compatibility? Or are there any realistic scenarios which using the old syntax would be impossible by doing just joins?

Answer 1

I'll admit that muscle memory kicks in and sometimes I use the 89 way before thinking. But I do prefer the 92 method because it keeps the WHERE clause cleaner. The only conditions in the WHERE clause are the ones relevant to your business case while the criteria that exist simply to define relationships are neatly in JOIN clauses.