How to get First date of month in Spark SQL?

Question

I need to get the first date of month of any date using Spark SQL.

I have date column in my table

Answer 1

date_add(last_day(add_months(<date_column>, -1)),1)

Answer 2

In pyspark (>= v1.5) you can use the trunc function:

import pyspark.sql.functions as sf

df.withColumn('first_of_month', sf.trunc('date_col', 'month'))