Spark SQL: org.apache.spark.sql.AnalysisException: cannot resolve "some columns" given input columns.

[Jerry Wong]

Hi,

Two JSON files but one of them miss some columns, like

{"firstName": "Jack", "lastName": "Nelson"}
{"firstName": "Landy", "middleName": "Ken", "lastName": "Yong"}

slqContext.sql("select firstName as first_name, middleName as middle_name,
lastName as last_name from jsonTable)

But there are an error
org.apache.spark.sql.AnalysisException: cannot resolve 'middleName' given
input columns firstName, lastName;

Can anybody give me your wisdom or any suggestions?

Thanks!
Jerry