Hi everyone, help please! I am very new to using SAS and I would like to combine two datasets by ID and Date. Some visits in the two datasets fall on the same date while some can be different +/- 90 days. Please see the below for example datasets. Dataset One ID Date Pulse Rate 1 4/2/18 85 1 10/3/19 90 1 3/2/20 75 2 10/2/18 85 2 15/3/19 69 2 25/2/20 99   Dataset Two ID Date BP 1 4/2/18 125 1 15/5/19 110 1 3/2/20 100 2 10/2/18 160 2 15/3/19 150 2 12/12/19 120   The output dataset I want is  ID Date Pulse Rate BP 1 4/2/18 85 125 1 10/3/19 90 110 1 3/2/20 75 100 2 10/2/18 85 160 2 15/3/19 69 150 2 25/2/20 99 120   As you can see, some visits are on different dates. But I want to merge them if the date in Dataset Two is within  +/- 90 days of the Dataset One. Could you please advise how to write the script for this. Thanks in advance.   ... View more