Dataframe is unreachable outside the if clause. how to access Dataframe outside if/else block

Requirement: DataSource id SQL Server and from structured data prepare JSON Scenario: Based on region value will populate data and will fit it within main dataframe. Problem occurred when I am trying to access dataframe outside the if/else clause. Below is the code sample that I have tried:

if(region == "UK")
    {
        val dfUK = "select * from tablename"
    }
    dfuk.withColumnRenamed("ColumnName1","ColumnName2")


    
    **Error: dfuk is unreachable**

CodePudding user response：

Resolution:

1. Import the library - import org.apache.spark.sql.DataFrame
2. Create blank dataframe:

    var outputdf: DataFrame = _
    if(region == "UK")
    {
        val dfUK = "select * from tablename"
        outputdf = dfUK 
    }
    outputdf.withColumnRenamed("ColumnName1","ColumnName2")

CodePudding user response：

define it as an expression

val dfUK = if(region == "UK") { 
   spark.sql("select * from tablename")
} //else something other definition for the df    
dfUK.withColumn...