Get previous row value

Hi Anon29 ,

I would assume that the date has to be considered in the calculation  as well and not just the time. If so,  create a datetime column first. If those two columns are in the proper date type, you should be able to add both.

datetime =
'table'[date] + 'table'[time]

then this column to acccess the previous record that is preceding the current time and which is equal to the current row customer

Previous Purchase =
CALCULATE (
    LASTNONBLANK ( 'table'[product], 1 ),
    FILTER (
        FILTER ( 'table', 'table'[customer id] = EARLIER ( 'table'[customer id] ) ),
        'table'[datetime] < EARLIER ( 'table'[datetime] )
    )
)

If you don't need to consider the date, just keep the datetime calculated column and use 'table'[time instead] in the second calc column formula.