WHERE clause before INNER JOIN

Question

If I have

SELECT * FROM Table1 t1 
LEFT JOIN Table2 t2 ON t1.id = t2.id 
WHERE t1.user=\'bob\';

Does the WHERE clause run afte

Answer 1

In my experience in a left join you cannot exclude records in the 'left' (t1) table in the ON-statement since - by definition - all t1 records will be included. The where statement does work as it will be applied to the result of the join afterwards.

I do not exactly know what you want to achieve but most probably an inner join suits your needs as well and then you can add the t1.user='bob' condition to the ON-statement.

But if Mosty Mostacho is correct, the location (WHERE vs ON) of the condition is not relevant for speed of execution.