pub fn first_value<T: SqlType + SingleValue, value>(
value: value,
) -> first_value<T, <value as AsExpression<T>>::Expression>where
value: AsExpression<T>,Expand description
Value of argument from first row of window frame
Returns value evaluated at the row that is the first row of the window frame.
This function must be used as window function. You need to call at least one
of the methods WindowExpressionMethods from to use this function in your SELECT
clause. It cannot be used outside of SELECT clauses.
let res = posts
.select((title, user_id, first_value(id).partition_by(user_id)))
.load::<(String, i32, i32)>(connection)?;
let expected = vec![
("My first post".to_owned(), 1, 1),
("About Rust".into(), 1, 1),
("My first post too".into(), 2, 3),
];
assert_eq!(expected, res);