SAS DI LAG1 alternative?

Question

Trying to use the LAG function in SAS to replicate a piece of code in a migration into SAS DI, however there doesn't seem to be the same function in SAS DI at all. Using SAS DI 4.21 currently, with a view to move up to 4.9 soon.

So my question is, is there an alternative way of replicating the following code in SAS DI:

DATA work.dm_chg_bal;
SET tmp_bal_chg;
FORMAT dt2 date9.;
acct_id2 = LAG1(acct_id);
app_suf2 = LAG1(app_suf);
dt2 = LAG1(start_dt);
RUN;

Cheers,

Answer 1

For this I would use a User Written transform. There is really no issue with doing this so long as you are diligent enough to perform the variable mapping - hence retaining the data lineage in metadata.

An explanation of this is available here.

Answer 2

I don't know the DI Studio transformations well (I typically only use the User Written transform).

I wonder if there is a transformation you could trick into generating:

data work.dm_chg_bal;
  set tmp_bal_chg;
  output;
  set tmp_bal_chg(rename=(acct_id=acct_id2 app_suf=app_suf2 start_dt=dt2));
run;

or

data work.dm_chg_bal;
  if _n_ > 1 then set tmp_bal_chg(rename=(acct_id=acct_id2 app_suf=app_suf2 start_dt=dt2));
  set tmp_bal_chg;
run;

If not, I'm sure there are data transformations that would allow you to make two copies of the dataset, one with ID=_n_ and the other with ID=_n_+1, and then merge by ID. That is, generate:

data main;
  set tmp_bal_chg;
  ID = _n_ ;
run;

data lag;
  set tmp_bal_chg (rename=(acct_id=acct_id2 app_suf=app_suf2 start_dt=dt2));
  ID = _n_ + 1;
run;

data work.dm_chg_bal;
  merge main (in=a)
        lag (keep=id acct_id2 app_suf2 dt2 in=b)
  ; 
  by id;
  if a;
run;