I have a dataset of test scores. My variables are (test taker’s) ID_no, test date, test score, and test type (online or in person). Some people took the test online and in person, and therefore, are in the dataset more than once. I’d like to make a new dataset with only those whose ID_no shows up more than once. And then with that dataset, I’d like to clean it to only include the most recent test date for each ID_no. I'm not super familiar with SQL and want to develop this skill. What kind of procedure would I need to use to achieve this?
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