How to use calendar table?

[Syndicate_Admin]

Hello. I have two questions about when to create a new calendar table. For example, if there is a Fact table in the data model with many records that already includes a date column. Why would it be necessary to create a new table with only the dates? I've seen that they do it but I don't know the reason.

On the other hand, if the Fact table has multiple columns of dates (e.g., purchase date, sale date, etc.), which column does the new calendar table connect to? Is there a difference between choosing one column or another?

Thank you.

[Syndicate_Admin]

Thank you, now it is clearer to me

[Ritaf1983]

Thanks for your kind words. Please mark my answer as a solution so that others can find it if there is a similar question 

[Ritaf1983 · Accepted solution]

A calendar table allows you to run reports with flexibility, efficiency, and most importantly, it is necessary for time intelligence functions.
Therefore, every model should include such a table (sometimes more than one).

Even when fact tables include a date column.
The subject is quite popular, and I attach links to two articles that provide a concise overview and instructions for producing the table.
1.https://www.red-gate.com/simple-talk/databases/sql-server/bi-sql-server/using-calendars-and-dates-in...
2.https://databear.com/power-bi-tip-dynamic-calendar-table/
If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.