joining multiple parquet files

[roni]

Hi ,
 I have 4 parquet files and I want to find data which is common in all of
them
e.g

SELECT TableA.*, TableB.*, TableC.*, TableD.* FROM (TableB INNER JOIN TableA
    ON TableB.aID= TableA.aID)
    INNER JOIN TableC ON(TableB.cID= Tablec.cID)
    INNER JOIN TableA ta ON(ta.dID= TableD.dID)
    WHERE (DATE(TableC.date)=date(now()))


I can do a 2 files join like -  val joinedVal =
g1.join(g2,g1.col("kmer") === g2.col("kmer"))

But I am trying to find common kmer strings  from 4 files.

Thanks

Roni