Answer
The DV fields are used by ServiceNow to provide a human-readable value for the ID fields that are used to establish relationships between the tables. Including them automatically could interfere with creating joins with other ServiceNow tables or other data connections.To see these values in Tableau Desktop, the appropriate joins should be made between the ServiceNow tables.
For example, the display values for the ID fields in the Catalog Task table can be included by making the following joins:

The joins are made on these fields:
- Assignment group = Sys ID (Group)
- Requested Item = SyS ID (Requested Item)
- Parent = Sys ID (Task)
- Opened by = Sys ID (User)
Sometimes, however, it may not be obvious which tables should be joined to find the display values. In these cases the REST Explorer in ServiceNow can be used to find the matching tables and fields:
- Set up a query for the primary table (e.g. Catalog Task) in the REST Explorer
- Find a field in the results that shows a link instead of a value:
"parent": {
"link": "<link .../api/now/table/task/...",
"value": "<value>"
},
- "parent" is the field you will join from Catalog task to the table listed after /api/now/table - in this case "task"
- Most likely it will be sys_id in that table you will join on, to be sure:
- Change your query to that table (task)
- In sysparam_query: Enter sys_id=<value> where <value> is the value listed in #2
- You should see the sys_id in the result:
"sys_id": "<value>",
- As well as the value you were trying to get:
"number": "<number>",
- Set up the join in Tableau Desktop using these tables and fields
Note: On any of these queries you can set sysparam_display_value to true instead of false to see what the related actual values are expected to be.