First, create an excel sheet with some dummy data as below image.

Figure 1:

Now, Steps are given below

Steps 1: First calculate Current month into current Month column using TODAY function as below

=MONTH(TODAY())

Figure 2:

Step 2: Now calculate Employee’s birthday month as below

=MONTH([@DOB])

Figure 3:

Step 3: Now check birthday month with current moth. If “Current month” value equal to “Month of Birth” then return yes as alert in “Alert” column as below image

=IF([@[Current Month]]=[@[Month of Birth]],"yes","")

Figure 4:

Hence, Figure 4 display, two person’s birthday.