Given:

```
val df = Seq((1L, "04-04-2015")).toDF("id", "date")
val df2 = df.withColumn("month", from_unixtime(unix_timestamp($"date", "dd/MM/yy"), "MMMMM"))
df2.show()

```

I got this output:

```
+---+----------+-----+
| id|      date|month|
+---+----------+-----+
|  1|04-04-2015| null|
+---+----------+-----+

```

However, I want the output to be as below:

```
+---+----------+-----+
| id|      date|month|
+---+----------+-----+
|  1|04-04-2015|April|
+---+----------+-----+

```

How can I do that in sparkSQL using Scala?