Function json_not_exists 

pub fn json_not_exists<'a, L>(
    left: L,
    path: &'a str,
) -> SQL<'a, SQLiteValue<'a>>
where
    L: ToSQL<'a, SQLiteValue<'a>>,

Create a JSON field does not exist condition

Example

let column = SQL::<SQLiteValue>::raw("metadata");
let condition = json_not_exists(column, "$.theme");
assert_eq!(condition.sql(), "json_type( metadata , ? ) IS NULL");