streamstats can be used to display Row Number in Splunk table.

streamstats in Splunk Query helps us to add cumulative summary statistics to all search results in a streaming manner. So, we can use count summary statistic to display as Row Number.

Please check the sample Splunk Query for reference.

Sample Splunk Query:

Your regular Query
| streamstats count as No
| table No, field1, field2, field3