Sebastian Hennebrueder <[EMAIL PROTECTED]> writes: > -- the following query has a inner join and an implicit join and does > not work. > select a.name as act_name, > u.name as trainer > from > activity a, > localgroup lg, > sponsor spon > inner join tuser u on a.fk_trainer=u.id > where spon.name='Jimmy Rich' > and > spon.fk_localgroup=lg.id > and lg.fk_activity=a.id
I think you were brought up on MySQL, which has only a vague relationship to actual SQL :-(. Per the SQL standard, what you wrote is equivalent to ... from ((activity a cross join localgroup lg) cross join (sponsor spon inner join tuser u on a.fk_trainer=u.id)) where ... Notice the parenthesization. Table a is not part of the spon/u join and so the reference to it from the spon/u ON condition is invalid. MySQL, unfortunately, seems to render the above syntax as ... from (((activity a cross join localgroup lg) cross join sponsor spon) inner join tuser u on a.fk_trainer=u.id) where ... in which case the reference from the ON condition is valid. Basically they think that comma and JOIN in the FROM list have the same precedence and associate left-to-right ... but any casual glance at the spec's syntax rules shows this is wrong. JOIN is supposed to bind more tightly than comma. regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 3: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq