Combining Rows with Multiple Columns by ID in SAS EG

Question

I have a table that has an ID column and multiple DATE columns. Each ID row is repeated each time it has data in a date column. I am looking to combine the rows so that there is a single row for each ID, with the data for all date columns populated.

Image of my current output

Image of the output I am looking for.

I have tried transposing and sorting the data, then running PROC SQL with a group by clause for ID_COLUMN

Answer 1

Let me show you one of my favorite SAS trick to perform this kind of operation.
Assumption is that the data is already sorted by id_column

data want;
update have(obs=0) have;
by id_column;
run;

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Let's take this minimal reproducible example (next time give your input with a table instead of a picture)

id_column  date1   date2    date3
  id_1    51.29405   .        .
  id_1       .       .     50.84405
  id_2    71.99253   .        .
  id_2       .       .     63.62253
  id_2       .    93.4383     .

data want;
update have(obs=0) have;
by id_column;
run;

id_column   date1    date2    date3
  id_1    51.29405     .     50.84405
  id_2    71.99253  93.4383  63.62253