The code block displayed below contains an error.

The "outer" argument should be eliminated, since "outer" is the default join type.

The join type needs to be appended to the join() operator, like join().outer() instead of listing it as the last argument inside the join() call.

The term [itemsDf.itemId, transactionsDf.productId] should be replaced by itemsDf.itemId == transactionsDf.productId.

The term [itemsDf.itemId, transactionsDf.productId] should be replaced by itemsDf.col("itemId") == transactionsDf.col("productId").

The "outer" argument should be eliminated from the call and join should be replaced by joinOuter.