It is a bit frustrating, when you know what you want but lack the syntax
In the picture is table 1, id like that any number that is in the input column gets compared with all the numbers of column A of table 2. It has to find the nearest number of the column A wich is always higher than input.
Once it found it, it has to watch column B on the same row and copy that to table 1, column output.
In the example i just fill that out by hand so it explains it better.