I am trying to convert the lag function to use in access-sql, which simply doesn’t have the function. So I have a table A with columns Z_type (a,b or c),Decider (1 or 2), Z_dates and Values..I would like to create another column which simply shifts the values down one date, with the first value then being null.

I tried to use this thread below, but I guess I’m doing something wrong still:

Calculating difference in column value from one row to the next

I tried several versions from the thread.