merging dataset with the nearest earlier date

[aarony]

i have a dataset.

ticker date            value

a        19991231     1

a        20011231     2

a        20031231     3

i have another dataset

ticker date

a         20030101

i want to find the nearest earlier date from the first dataset and arrive at the following:

ticker date             value

a         20030101       2

could you provide me of your guidance? thx in advance.

[Astounding]

I'm sure SQL can handle this if you are more inclined in that direction.  But a DATA step can do it as well:

data want (drop=value rename=(latest_value=value));

set a_dataset (in=in1)

   another_dataset (in=in2);

by ticker date;

if first.ticker then latest_value=.;

if in1 then latest_value=value;

retain latest_value;

if in2;

run;

[aarony]

dear astounding. thx so much! for ur kind help!

[aarony]

hi astounding, sorry but would u mind helping me once more?

for some reason, i am not getting the value 2. rather i am getting 3.

thx much

[Astounding]

Check that your data sets are mentioned in the proper order:

set a_dataset (in=in1)

   another_dataset (in=in2);

The first data set should be the one with multiple records per ticker.

If that's not the issue, I would need to see a few lines of data that are causing the problem.

Also note, if both data sets contain the same date value, this program selects the matching date (not an earlier date).  That can be changed if necessary.