Spark Equivalent of IF Then ELSE

Question

I have seen this question earlier here and I have took lessons from that. However I am not sure why I am getting an error when I feel it should work.

I want to crea

Answer 1

Correct structure is either:

(when(col("iris_class") == 'Iris-setosa', 0)
.when(col("iris_class") == 'Iris-versicolor', 1)
.otherwise(2))

which is equivalent to

CASE 
    WHEN (iris_class = 'Iris-setosa') THEN 0
    WHEN (iris_class = 'Iris-versicolor') THEN 1 
    ELSE 2
END

or:

(when(col("iris_class") == 'Iris-setosa', 0)
    .otherwise(when(col("iris_class") == 'Iris-versicolor', 1)
        .otherwise(2)))

which is equivalent to:

CASE WHEN (iris_class = 'Iris-setosa') THEN 0 
     ELSE CASE WHEN (iris_class = 'Iris-versicolor') THEN 1 
               ELSE 2 
          END 
END

with general syntax:

when(condition, value).when(...)

or

when(condition, value).otherwise(...)

You probably mixed up things with Hive IF conditional:

IF(condition, if-true, if-false)

which can be used only in raw SQL with Hive support.