MySQL Error Unknown column in 'on clause'

Question

I've tried to join 3 tables: a, b and c.

my current code:

SELECT a.a_id, a.variable1, a.variable2 FROM b
LEFT JOIN a ON a.a_id = b.a_id
LEFT JOIN c ON c.c_id = b.c_id
WHERE  a.variable1 IN ('1', '4');

now I get

"Unknown column 'a.id' in 'on clause'".

but I'm not sure how I can avoid this error.

I'm a major beginner so please lots of explanation

_“now i get "Unknown column 'a.id' in 'on clause'".”_ - rather hard to believe, since your statement does not contain `a.id` in any of the ON clauses. — CBroe, Nov 28 '17 at 14:04

score 0 · Accepted Answer · answered Nov 28 '17 at 14:05

0

Maybe this is the cause:

LEFT JOIN a ON a.a_id = b.a_id

should probably be

LEFT JOIN a ON a.a_id = b.b_id

and (?)

LEFT JOIN c ON c.c_id = b.b_id

answered Nov 28 '17 at 14:05

Johannes

1 Answers1