use std::fmt::Write;
use super::filter::Filter;
use super::Predicate;
use crate::sql::{CheckedSql, ToSql};
pub mod group;
pub use group::{GroupBy, GroupOrder};
pub mod join;
pub use join::{Join, Joined};
pub mod order;
pub use order::{Order, OrderBy};
pub mod queryable;
pub use queryable::{Queryable, WildCard, WriteQueryable};
mod selectable;
pub use selectable::{SelectStatement, Selectable};
pub trait Select: ToSql {
type Selectable: Selectable;
type Queryable: WriteQueryable;
}
impl<S, Q> Select for SelectStatement<S, Q>
where
S: Selectable,
Q: WriteQueryable,
{
type Selectable = S;
type Queryable = Q;
}
impl<S, Q, P> Select for Filter<SelectStatement<S, Q>, P>
where
S: Selectable,
Q: WriteQueryable,
P: Predicate,
{
type Selectable = S;
type Queryable = Q;
}
#[derive(Debug, Clone, Copy)]
pub struct Limit<Q> {
queryable: Q,
limit: usize,
}
impl<Q> Limit<Q> {
#[inline(always)]
pub(crate) const fn new(queryable: Q, limit: usize) -> Self {
Self { queryable, limit }
}
}
impl<Q: Select> Select for Limit<Q> {
type Selectable = Q::Selectable;
type Queryable = Q::Queryable;
}
impl<Q: Select> ToSql for Limit<Q> {
fn write_sql_unchecked(&self, sql: &mut String) {
self.queryable.write_sql_unchecked(sql);
sql.write_fmt(format_args!(" LIMIT {}", self.limit))
.unwrap();
}
}
impl<Q: CheckedSql> CheckedSql for Limit<Q> {}