Hi All,
I am trying to populate a column using an IF function, but not sure how to do it. Basically, I want use an IF function to check if a row in a column is null, and if it is, I want to replace it with the first 4 characters of a different row. I've attached an example to help visualise (For the rows that are Null, I want the first 4 letters ie 2017, 2018 and 2011 to populate the year column):

Any help would be appreciated.
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Cheers!