Hi, Ufoo!
Maybe I misunderstood your question but...
Excel store dates as integer numbers starting for 01/01/1900 as 1. That's about storage.
Excel show stored dates according to the cell format, i.e., it maybe dd/mm/yyyy, mm/dd/yyyy, dd-mmm, including dd, mmmm... Taking the above date as example: 01/01/1900, 01/01/1900, 01-Jan, 01, January. That's about displaying.
The useful point is that all the displayed values (let us assume that orginal date is in A1 and cells B1:B5 contain "=$A$1") represent the same date. So the MATCH function will operate flawlessly independently of the cell format but accordingly to the cell value.
In your question, let us say A1 holds 22/07/2017 and B1:B5 holds the posted dates, in C1 you can place this formula:
C1: =MATCH(A1;B1:B5;0)
This for an exact match, if the date displayed as Jul-17 doesn't correspond to day 17 (which is not displayed since format is mmm-yy) it will return a N/A error.
C1: =MATCH(A1;B1:B5;1)
This for a less or equal match, if the date displayed as Jul-17 (B1) is greater than A1 it will return a N/A error.
C1: =MATCH(A1;B1:B5;-1)
This for a greater or equal match, if the date displayed as Nov-17 (B5) is lesser than A1 it will return a N/A error.
Hope it helps.
Regards!