Amigo de mis amigos (Amigos en comun)

[freedatos]

eso tira error SQL


Error
consulta SQL:

SELECT *
FROM amigos a
WHERE a.id_usuario =17
AND a.id_amigo
IN (


SELECT b.id_amigo
FROM amigos b
WHERE b.id_usuario =12
LIMIT 0 , 30
MySQL ha dicho:

#1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 2