In Wrangler, the Merge directive works with two columns only. If you need to merge three or more columns, use multiple merge steps in your recipe. The following example merges the records in two string columns, column_a and column_b with the strings separated by “|” and creates a new column called newcol_a_b that contains the merged records.
merge :column_a :column_b :newcol_a_b ‘|’
To merge a third column, column_c, with newcol_a_b, add another merge step to the recipe:
merge :colnew_a_b :column_c :newcol_a_b_c ‘|’