Counting matching duplicates from another column

[Anonymous]

I can't figure out a way to calculate the repeat of an ID based on a key column.

For example

key       |    related   | count

a0001   |    (blank)   |    3

a0002   |   a0004     |   0

a0003   |   a0004     |   0

a0004   |   (blank)    |   2

a0005   |   a0001     |   0

a0006   |   a0001     |   0

a0007   |   a0001     |   0

Trying to figure out the count of the related repeats based on the key.

[Anonymous · Accepted solution]

CountRepeat = var thisRecord = [key]
RETURN
CALCULATE(
        countrows('YourTable'),
        all('YourTable'),
        'YourTable'[related] = thisRecord
)