Count (Field) if (field = XX)

[Leooo]

Hello,

I'd like to count a field based on another field.

For example, I've created a field to count my user based on their "create date". ( COUNT(create date))

I'd like to do a second field for those same users based on the "is user" field with the value "true". I don't want to create. filter because I need this field to create a formula later on. For me, it should be a combination of "count(Create Date) and. IF(is User = true) but the following doesn't work:: 

COUNT(Create Date IF(is user=true))

I've also tried to only count the "COUNT(is user="true")", but it doesn't work. it returns 1 where it should be 1'110.