The number of differences in a column

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情深已故
情深已故 2021-01-29 07:18

I would like to retrieve a column of how many differences in letters in each row. For instance

If you have a a value \"test\" and another row has a value \"testing \", t

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  •  萌比男神i
    2021-01-29 07:58

    I think what you are looking for is a measure of edit difference, rather than just counting prefix similarity, for which there are a few common algorithms. Levenshtein's method is one that I've used before and I've seen it implemented as TSQL functions. The answers to this SO question suggest a couple of implementations in TSQL that you might just be able to take and use as-is.

    (though take time to test the code and understand the method rather than just copying the code and using it, so that you can understand the output if something seems to go wrong - otherwise you could be creating some technical debt you'll have to pay back later)

    Exactly which distance calculation method you want will depend on how you want to count certain things, for instance do you count a substitution as one change or a delete and an insert, and if your strings are long enough for it to matter do you want to consider substring moves, and so forth.

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