MySQL Performance: JOIN ON vs WHERE [duplicate]

Answer 1

Here is a good analysis of these two approaches: SQL left join vs multiple tables on FROM line?

This explanation is general, I'm not too sure what MySQL does in this matter; but either way the point is that a JOIN is always more explicit and clear and can be moved from one engine to another with no major changes in the logic of the query.

Answer 2

I suspect that using "JOIN" is doing a "LEFT JOIN". Try using an "INNER JOIN" and see if the explain statement is the same.

SELECT <field names>
FROM <table1>
INNER JOIN <table2> ON <join_condition>
INNER JOIN <table3> ON <join_condition> 
INNER JOIN <table4> ON <join_condition> 
...

When using an inner join, I would not expect there to be a performance difference between your two queries. I would worry more about having the proper indexes. Make sure the join conditions can make a match using an indexed column.