Below is my input table
Items, Month
1, Jan
2, Jan
7, Jan
3, Jan
8, Jan
3, Feb
4, Feb
5, Feb
1, Feb
2, Feb
7, Mar
5, Mar
10, Mar
9, Mar
2, Mar
6, Mar
1, Apr
8, Apr
3, Apr
7, Apr
9, Apr
1, May
5, May
48, May
50, May
o/p
jan, feb, mar, apr, may
0, 3, 2, 4, 3
Jan: As the output Jan has no previous months so it should show 0
Feb: We have values for Feb 1,2,3 and common with Jan, the count should show 3
Mar: We have values for Mar 2 which is common with Jan & Feb, count should show 2
Apr: We have values for Apr 1,3 which is common with Jan, Feb & Mar, so count shows 4
May: We have values for May 1 which is common with Jan, Feb & Apr, so the count shows 3
Thanks