Forum Discussion
Need Help Creating a Unified Table Visual from Multiple Unrelated Data Sources in Power BI
The approach you are using should work, but you need to make sure that the date columns you are using in all the models are just dates, not datetimes. The disconnected table you are using will be fine, as you are generating that using CALENDAR and so it will not have a datetime part, but in the other models you need to make sure that the column is set to date both in Power BI Desktop and in Power Query - if you only do it in desktop but not in Power Query it will retain the time information even though it won't show it.
Once you are happy that all columns are purely dates you could use TREATAS as you have suggested, or you could create one-to-many relationships from the date table in the combined model to both date tables in the other models, so that filters flow from the combined model to the other models. That would negate the need to amend any calculations and you would be able to use the base measures from both models.
The approach you are using should work, but you need to make sure that the date columns you are using in all the models are just dates, not datetimes. The disconnected table you are using will be fine, as you are generating that using CALENDAR and so it will not have a datetime part, but in the other models you need to make sure that the column is set to date both in Power BI Desktop and in Power Query - if you only do it in desktop but not in Power Query it will retain the time information even though it won't show it.
Once you are happy that all columns are purely dates you could use TREATAS as you have suggested, or you could create one-to-many relationships from the date table in the combined model to both date tables in the other models, so that filters flow from the combined model to the other models. That would negate the need to amend any calculations and you would be able to use the base measures from both models.