Coalesce Columns

It lets the user create a new field with the value being formed by getting the first non null value from the list of columns provided by the user.

This transformation expects user to provide below inputs:

Input Arguments	Mandatory	Default Value	Description
new-column-name	Yes	-	The name of new column to be created.
columns-to-coalesce	Yes	-	The list of columns to perform coalesce operation on.

For example, consider we have below restonomer response in json:

{
  "col_A": null,
  "col_B": "Pune",
  "col_C": null
}

Now, suppose the requirement is to create a new column col_D having the value which is equal to the first non null value from the list of columns col_A, col_B and col_C. Then, user can configure the CoalesceColumns transformation in the below manner:

{
  type = "CoalesceColumns"
  new-column-name = "col_D"
  columns-to-coalesce = ["col_A", "col_B", "col_C"]
}

The transformed response will now have the col_D field as below:

{
  "col_A": null,
  "col_B": "Pune",
  "col_C": null,
  "col_D": "Pune"
}