Coalesce is commonly used with Transform maps in ServiceNow. It is used to set a field as unique, so that when data is imported :
- If ServiceNow identifies the data against an existing record using Coalesce, then it will update that record.
- If ServiceNow identifies the data against no existing records, it creates a new one.
So lets take this as a simple example, we want to load the below User information through Transform Maps into our User table. We set Employee ID as the Coalesce field
Here is the data we are loading in.
| Employee ID | Name | Country | Role |
| 001 | John | Ireland | Sales |
| 002 | Sarah | England | IT |
| 003 | Amy | Scotland | HR |
| 004 | Brad | America | Marketing |
Here is the data that exists in the User table already
| Employee ID | Name | Country | Role |
| 001 | John | | Sales |
| 002 | Sarah | England | |
| 003 | | Scotland | HR |
Here is what the table would look like after the transform map runs
| Employee ID | Name | Country | Role |
| 001 | John | Ireland | Sales |
| 002 | Sarah | England | IT |
| 003 | Amy | Scotland | HR |
| 004 | Brad | America | Marketing |
