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use crate::ast::{ConditionTree, Table};
/// The `JOIN` table and conditions.
#[derive(Debug, PartialEq, Clone)]
pub struct JoinData<'a> {
pub(crate) table: Table<'a>,
pub(crate) conditions: ConditionTree<'a>,
}
impl<'a> JoinData<'a> {
/// Implement a join with no conditions.
pub fn all_from(table: impl Into<Table<'a>>) -> Self {
Self { table: table.into(), conditions: ConditionTree::NoCondition }
}
}
impl<'a, T> From<T> for JoinData<'a>
where
T: Into<Table<'a>>,
{
fn from(table: T) -> Self {
Self::all_from(table)
}
}
/// A representation of a `JOIN` statement.
#[derive(Debug, PartialEq, Clone)]
pub enum Join<'a> {
/// Implements an `INNER JOIN` with given `JoinData`.
Inner(JoinData<'a>),
/// Implements an `LEFT JOIN` with given `JoinData`.
Left(JoinData<'a>),
/// Implements an `RIGHT JOIN` with given `JoinData`.
Right(JoinData<'a>),
/// Implements an `FULL JOIN` with given `JoinData`.
Full(JoinData<'a>),
}
/// An item that can be joined.
pub trait Joinable<'a> {
/// Add the `JOIN` conditions.
///
/// ```rust
/// # use sqlint::{ast::*, visitor::{Visitor, Sqlite}};
/// # fn main() -> Result<(), sqlint::error::Error> {
/// let join_data = "b".on(("b", "id").equals(Column::from(("a", "id"))));
/// let query = Select::from_table("a").inner_join(join_data);
/// let (sql, _) = Sqlite::build(query)?;
///
/// assert_eq!(
/// "SELECT `a`.* FROM `a` INNER JOIN `b` ON `b`.`id` = `a`.`id`",
/// sql,
/// );
/// # Ok(())
/// # }
/// ```
fn on<T>(self, conditions: T) -> JoinData<'a>
where
T: Into<ConditionTree<'a>>;
}
impl<'a, U> Joinable<'a> for U
where
U: Into<Table<'a>>,
{
fn on<T>(self, conditions: T) -> JoinData<'a>
where
T: Into<ConditionTree<'a>>,
{
JoinData { table: self.into(), conditions: conditions.into() }
}
}
impl<'a> Joinable<'a> for JoinData<'a> {
fn on<T>(self, conditions: T) -> JoinData<'a>
where
T: Into<ConditionTree<'a>>,
{
let conditions = match self.conditions {
ConditionTree::NoCondition => conditions.into(),
cond => cond.and(conditions.into()),
};
JoinData { table: self.table, conditions }
}
}