Apologies, newbie here (thanks, edited formatting) I'm querying some Mysql, which is working when I have a value with use mysql::*; use mysql::prelude::*; .. let mut row = result_set.as_ref().unwrap(); let tag_string: <String> = row.get(4).unwrap(); Cargo.toml has mysql = "18.…

Can I ask you to use code blocks for the rest of the post as well instead of just marking the line as code with a single backtick?

As for your question, the purpose of get_opt is not to handle null values, but to handle values that have been taken using Row::take. To handle a null value, use get with T = Option<Something>. let tag_string: Option<String> = row.get(4).unwrap();

You may also consider using take instead of get, as it avoids some unnecessary copying.

Thanks, I had previously tried that, but had got an error... `row` is a `&` reference, so the data it refers to cannot be borrowed as mutable But I think that's likely a separate problem with my lack of understanding passing references.

To avoid the copying, the call to take removes the value from the row, meaning that it can only be taken once (hence why get_opt returns a Result). This modifies the Row, so you must use a mutable reference.

Thanks Alice, much appreciate the help.

Lifetime params for more complex function returns

alice July 7, 2020, 5:18pm 2

You can read more about formatting here, and note that you can edit the post.

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Lifetime params for more complex function returns

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