How to use Column.isin with list?

Question

val items = List("a", "b", "c")

sqlContext.sql("select c1 from table")
          .filter($"c1".isin(items))
          .collect
          .foreach(println)

The code above throws the following exception.

Exception in thread "main" java.lang.RuntimeException: Unsupported literal type class scala.collection.immutable.$colon$colon List(a, b, c)
at org.apache.spark.sql.catalyst.expressions.Literal$.apply(literals.scala:49)
at org.apache.spark.sql.functions$.lit(functions.scala:89)
at org.apache.spark.sql.Column$$anonfun$isin$1.apply(Column.scala:642)
at org.apache.spark.sql.Column$$anonfun$isin$1.apply(Column.scala:642)
at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:245)
at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:245)
at scala.collection.IndexedSeqOptimized$class.foreach(IndexedSeqOptimized.scala:33)
at scala.collection.mutable.WrappedArray.foreach(WrappedArray.scala:35)
at scala.collection.TraversableLike$class.map(TraversableLike.scala:245)
at scala.collection.AbstractTraversable.map(Traversable.scala:104)
at org.apache.spark.sql.Column.isin(Column.scala:642)

Answer 1

According to documentation, .isin takes a vararg, not a list. So, I will suggest you to covert it into vararg and then proceed. Try doing this:

val items = List("a", "b", "c")

sqlContext.sql("select c1 from table")

          .filter($"c1".isin(items:_*))

          .collect

          .foreach(println)

Your variant with mkString compiles, because one single String is also a vararg (with number of arguments equal to 1), but it is probably not what you want to achieve.