OTBI Analysis to get a value from the latest project budget version

I have created an OTBI analysis that shows values from the
original budget version , but I want to compare it with the same values
of the latest budget version, but when I use the function of LAST I get
the error

Invalid Alias Format : Table_name.Column_name required. OK (Ignore Error)

my query is

CASE
WHEN "Project Budget Version"."Budget Key" = last("Project Budget
Version"."Budget Key") THEN (ifnull ( cast( "- Budget Line Record
Information"."PJO_PLAN_LINES_DFF_APRFT_SCLTN_NT_" as numeric) ,0) ) ELSE
0

what would be the error or the best approach to reach my goal ?