Function trim_array

pub fn trim_array<Arr: ArrayOrNullableArray + SingleValue, a, n>(
    a: a,
    n: n,
) -> trim_array<Arr, a, n>
where
    a: AsExpression<Arr>,
    n: AsExpression<Integer>,

Available on crate feature postgres_backend only.

Trims an array by removing the last n elements. If the array is multidimensional, only the first dimension is trimmed.

Example

let trimmed_array = diesel::select(trim_array::<Array<Integer>, _, _>(vec![1, 2, 3, 4], 3))
    .get_result::<Vec<i32>>(connection)?;
assert_eq!(vec![1], trimmed_array);

let trimmed_array = diesel::select(trim_array::<Array<Nullable<Integer>>, _, _>(vec![Some(1), Some(2), Some(3)], 1))
    .get_result::<Vec<Option<i32>>>(connection)?;
assert_eq!(vec![Some(1), Some(2)], trimmed_array);

let trimmed_array = diesel::select(trim_array::<Array<Integer>, _, _>(Vec::<i32>::new(), 0))
    .get_result::<Vec<i32>>(connection)?;
assert_eq!(Vec::<i32>::new(), trimmed_array);

let trimmed_array = diesel::select(trim_array::<Nullable<Array<Integer>>, _, _>(None::<Vec<i32>>, 0))
    .get_result::<Option<Vec<i32>>>(connection)?;
assert_eq!(None, trimmed_array);

let trimmed_array = diesel::select(trim_array::<Nullable<Array<Integer>>, _, _>(None::<Vec<i32>>, 1))
    .get_result::<Option<Vec<i32>>>(connection)?;
assert_eq!(None, trimmed_array);