How to setup day month calculation in tableau?

Question

I have dataset on date of births e.g.

14-Dec-98,
23-Nov-70,
14-Dec-67,
7-Jan-19,
14-Dec-45,
7-Jan-88

I want to plot a graph of number of birthdays on a day. That is;

14-Dec -- 3,
23-Nov -- 1,
7-Jan --- 2,

How should I write the calculated field formula??

Answer 1

Assuming your date field is recognised by Tableau as a date, extract the day and month from that field.

DAY([DOB]) MONTH([DOB])

Combine these and make them back into a date (assuming the data source accepts MAKEDATE)

MAKEDATE(2020, MONTH([DOB]), DAY([DOB]))

Format the new made date field to remove the year.

Answer 2

Try this formula:

{ FIXED MONTH([Date of Birth]), DAY([Date of Birth]):COUNT([Number of Records])}