problem with nested inner joins in SQLIte

问题

The sql statement below will not run in SQLite:

select * 
from A
left join (B inner join C on B.fkC = C.pk) on A.optionalfkB = B.pk

I get a sqlException "unknown column B.pk"

According to the documentation @ http://www.sqlite.org/lang_select.html this should work, and it will work in all other sql implementations. Am I doing something wrong?

回答1:

It doesn't work because the "outer" query doesn't know what B is.

select * 
from A
left join (B inner join C on B.fkC = C.pk) B on A.optionalfkB = B.pk

The (B inner join C on B.fkC = C.pk) is weird without any select, but the specification does say that it is valid.

来源：https://stackoverflow.com/questions/7071283/problem-with-nested-inner-joins-in-sqlite