MySQL table join syntax

Question

If I use syntax like this

SELECT * FROM table_1, table_2 WHERE table_1.id=table_2.id;

is this an INNER JOIN? In other words, is this equivalent to

SELECT * FROM table_1 INNER JOIN table_2 ON table_1.id=table_2.id;

see this question: http://stackoverflow.com/questions/1018822/inner-join-on-vs-where-clause — Zak, Jul 29 '13 at 17:37
Thanks Zak. I worried that this was a duplicate but couldn't condense my question down to a search that answered my question. — Bill, Jul 29 '13 at 18:05

score 2 · Accepted Answer · answered Jul 29 '13 at 17:36

2

Short answer: Yes, it is the same.

Most RDBMS will eventually process both syntax the same way.

Using the INNER JOIN is considered to be better readable, and also is the ANSI standard.

answered Jul 29 '13 at 17:36

Bjoern

The other syntax is ANSI standard as well ;) – ypercubeᵀᴹ Jul 29 '13 at 18:18
I know, I just didn't put it in there to avoid a religious debate about it! :-) – Bjoern Jul 29 '13 at 18:26

score 1 · Answer 2 · answered Jul 29 '13 at 17:40

For simple cases like this, it appears that the MySQL engine will optimize in the same way. I figured this out by running

DESCRIBE SELECT * FROM table_1, table_2 WHERE table_1.id=table_2.id;

and

DESCRIBE SELECT * FROM table_1 INNER JOIN table_2 ON table_1.id=table_2.id;

which tells you a bit about how the query will run.

2 Answers2