count cells, then reset count when value in another cell changes

[Mitchell_Collen via OfficeKB.com]

I am trying to create a function that will assign number for TaskID. It will
restart a count everytime there is a '0' in the Step column. This will be
used for a database to group taskID and task separate. IF(a2 = 0, (0+1) <
this does not work. Do you know how to do this?

Step TaskID
0 1
1 1
2 1
0 2
1 2
2 2
3 2
4 2
0 3
1 3
2 3
3 3
4 3
5 3

 

[T. Valko]

One way...

Assuming the first entry is *always* 0.

Enter 1 in B2

Enter this formula in B3 and copy down as needed:

=IF(A3=0,B2+1,B2)

 

[Teethless mama]

Try this:

=COUNTIF($A$2:A2,0)
copy down

 

[Mitchell_Collen via OfficeKB.com]

Thanks!

 

[Teethless mama]

You're Welcome!