I have completed the first part of the article where it shows how to create individual rollup fields to show the last date one of those specific activities were completed - But the last paragraph where he explains on how to do a combined field while incorporating a calculated field has me a little lost.
Hoping someone can explain this process a little more clearly to me!
Here is the paragraph I am talking about:
"what if you want a single field for all activity types? Rollup fields do not allow you to select the Activity Pointer entity, so you can’t just create one rollup field to account for all activity types. However, it still can be done, using the rollup field’s cousin, a calculated field. Calculated fields perform calculation and aggregation of fields on the same entity or the direct parent. So If I create a rollup field to get the max date of all activity types, I can create a calculated field that gets the maximum value from each of the rollup fields."
Here is a link to the full article: http://us.hitachi-solutions.com/blog/2015/01/26/last-activity-date-in-dynamics-crm-2015/