title: Parse json file in U-SQL
body: <p>I'm trying to parse below Json file using USQL but keep getting error.</p>
  
  <pre><code>Json file@
  
  {"dimBetType_SKey":1,"BetType_BKey":1,"BetTypeName":"Test1"}
  {"dimBetType_SKey":2,"BetType_BKey":2,"BetTypeName":"Test2"}
  {"dimBetType_SKey":3,"BetType_BKey":3,"BetTypeName":"Test3"}
  </code></pre>
  
  <p>Below is the USQL script, I'm trying to extract the data from above file.</p>
  
  <pre><code>    REFERENCE ASSEMBLY [Newtonsoft.Json];
      REFERENCE ASSEMBLY [Microsoft.Analytics.Samples.Formats];
  
  DECLARE @Full_Path string =
  "adl://xxxx.azuredatalakestore.net/2017/03/28/00_0_66ffdd26541742fab57139e95080e704.json";
  
  DECLARE @Output_Path = "adl://xxxx.azuredatalakestore.net/Output/Output.csv";
  
  @logSchema =
  EXTRACT dimBetType_SKey int
  FROM @Full_Path
  USING new Microsoft.Analytics.Samples.Formats.Json.JsonExtractor();
  
  OUTPUT @logSchema
  TO @Output_Path 
  USING Outputters.Csv();
  </code></pre>
  
  <p>But the USQL is keep failing with Vertex error </p>
  
  <p>Any help?</p>