Thread: Need help with INNER Join

Mag Gam wrote:
> When I needed to join tables I always used the equal syntax (ie. SELECT
> id from foo,fee where id.foo=id.fee)
>
> To my understanding, it is preferred to use the INNER JOIN keyword. I am
> able to INNER JOIN 2 tables, but I am not sure of the syntax for 3 or
> more tables. Can someone please show me an example for that ?


Your example will not work; you should have written:

SELECT foo.id from foo,fee where foo.id=fee.id

With inner join, this would be

SELECT foo.id FROM foo
INNER JOIN fee on foo.id=fee.id

Joining a third table would look like

SELECT foo.id FROM foo
INNER JOIN fee ON foo.id=fee.id
INNER JOIN bar ON bar.id=foo.id

Am Sonntag, 4. Mai 2008 schrieb Mag Gam:

> To my understanding, it is preferred to use the INNER JOIN keyword. I am
> able to INNER JOIN 2 tables, but I am not sure of the syntax for 3 or more
> tables. Can someone please show me an example for that ?

Just concatenate the joins, modern servers do not need hints by brackets and
such:

select * from a join b on a.id=b.aid join c on b.id=c.bid ;

In that respect, also take a look on "join using" and "natural join".