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Posted to issues@spark.apache.org by "Maciej Bryński (JIRA)" <ji...@apache.org> on 2015/08/14 10:15:45 UTC

[jira] [Created] (SPARK-9970) SQLContext.createDataFrame failed to properly determine column names

Maciej Bryński created SPARK-9970:
-------------------------------------

             Summary: SQLContext.createDataFrame failed to properly determine column names
                 Key: SPARK-9970
                 URL: https://issues.apache.org/jira/browse/SPARK-9970
             Project: Spark
          Issue Type: Bug
          Components: PySpark
    Affects Versions: 1.4.0
            Reporter: Maciej Bryński
            Priority: Minor


Hi,
I'm trying to do "nested join" of tables.
After first join everything is ok, but second join made some of the column names lost.

My code is following:
def joinTable(tableLeft, tableRight, columnLeft, columnRight, columnNested, joinType = "left_outer"):
    print "Joining tables %s %s" % (namestr(tableLeft), namestr(tableRight))
    sys.stdout.flush()
    tmpTable = sqlCtx.createDataFrame(tableRight.rdd.groupBy(lambda r: r.asDict()[columnRight]))
    tmpTable = tmpTable.select(tmpTable._1.alias("joinColumn"), tmpTable._2.data.alias(columnNested))
    return tableLeft.join(tmpTable, tableLeft[columnLeft] == tmpTable["joinColumn"], joinType).drop("joinColumn")

user = sqlContext.read.json(path + "user.json")
user.printSchema()
root
 |-- id: long (nullable = true)
 |-- name: string (nullable = true)

order =  sqlContext.read.json(path + "order.json")
order.printSchema();
root
 |-- id: long (nullable = true)
 |-- price: double (nullable = true)
 |-- userid: long (nullable = true)

lines =  sqlContext.read.json(path + "lines.json")
lines.printSchema();
root
 |-- id: long (nullable = true)
 |-- orderid: long (nullable = true)
 |-- product: string (nullable = true)

orders = joinTable(order, lines, "id", "orderid", "lines")
orders.printSchema()

root
 |-- id: long (nullable = true)
 |-- price: double (nullable = true)
 |-- userid: long (nullable = true)
 |-- lines: array (nullable = true)
 |    |-- element: struct (containsNull = true)
 |    |    |-- id: long (nullable = true)
 |    |    |-- orderid: long (nullable = true)
 |    |    |-- product: string (nullable = true)

clients = joinTable(user, orders, "id", "userid", "orders")
clients.printSchema()

root
 |-- id: long (nullable = true)
 |-- name: string (nullable = true)
 |-- orders: array (nullable = true)
 |    |-- element: struct (containsNull = true)
 |    |    |-- id: long (nullable = true)
 |    |    |-- price: double (nullable = true)
 |    |    |-- userid: long (nullable = true)
 |    |    |-- lines: array (nullable = true)
 |    |    |    |-- element: struct (containsNull = true)
 |    |    |    |    |-- _1: long (nullable = true)
 |    |    |    |    |-- _2: long (nullable = true)
 |    |    |    |    |-- _3: string (nullable = true)


I tried to check if groupBy isn't the root of the problem but it's looks right
grouped =  orders.rdd.groupBy(lambda r: r.userid)
print grouped.map(lambda x: list(x[1])).collect()

[[Row(id=1, price=202.3, userid=1, lines=[Row(id=1, orderid=1, product=u'XXX'), Row(id=2, orderid=1, product=u'YYY')]), Row(id=2, price=343.99, userid=1, lines=[Row(id=3, orderid=2, product=u'XXX')])], [Row(id=3, price=399.99, userid=2, lines=[Row(id=4, orderid=3, product=u'XXX')])]]




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