Trait diesel::expression::expression_methods::global_expression_methods::ExpressionMethods [−] [src]

pub trait ExpressionMethods: Expression + Sized {
    fn aliased<'a>(self, alias: &'a str) -> Aliased<'a, Self> { ... }
    fn eq<T: AsExpression<Self::SqlType>>(self, other: T) -> Eq<Self, T::Expression> { ... }
    fn ne<T: AsExpression<Self::SqlType>>(self, other: T) -> NotEq<Self, T::Expression> { ... }
    fn is_null(self) -> IsNull<Self> { ... }
    fn is_not_null(self) -> IsNotNull<Self> { ... }
    fn gt<T: AsExpression<Self::SqlType>>(self, other: T) -> Gt<Self, T::Expression> { ... }
    fn ge<T: AsExpression<Self::SqlType>>(self, other: T) -> GtEq<Self, T::Expression> { ... }
    fn lt<T: AsExpression<Self::SqlType>>(self, other: T) -> Lt<Self, T::Expression> { ... }
    fn le<T: AsExpression<Self::SqlType>>(self, other: T) -> LtEq<Self, T::Expression> { ... }
    fn between<T: AsExpression<Self::SqlType>>(self, other: Range<T>) -> Between<Self, And<T::Expression, T::Expression>> { ... }
    fn not_between<T: AsExpression<Self::SqlType>>(self, other: Range<T>) -> NotBetween<Self, And<T::Expression, T::Expression>> { ... }
    fn desc(self) -> Desc<Self> { ... }
    fn asc(self) -> Asc<Self> { ... }
}

Provided Methods

fn aliased<'a>(self, alias: &'a str) -> Aliased<'a, Self>

Alias an expression for use alongside with.

While you will need to give it a name to alias as, you should not need to reference the alias elsewhere. You can pass the returned expression anywhere you want to reference the alias.

Example

let query = plain_to_tsquery(search_text).aliased("q");
let rank = ts_rank(query, indexed_search_column).aliased("rank");
crates.with(query).with(rank)
    .filter(query.matches(indexed_search_column))
    .order(rank.desc())

fn eq<T: AsExpression<Self::SqlType>>(self, other: T) -> Eq<Self, T::Expression>

Creates a SQL = expression.

Example

let data = users.select(id).filter(name.eq("Sean"));
assert_eq!(Ok(1), data.first(&connection));

fn ne<T: AsExpression<Self::SqlType>>(self, other: T) -> NotEq<Self, T::Expression>

Creates a SQL != expression.

Example

let data = users.select(id).filter(name.ne("Sean"));
assert_eq!(Ok(2), data.first(&connection));

fn is_null(self) -> IsNull<Self>

Creates a SQL IS NULL expression.

fn is_not_null(self) -> IsNotNull<Self>

Creates a SQL IS NOT NULL expression.

fn gt<T: AsExpression<Self::SqlType>>(self, other: T) -> Gt<Self, T::Expression>

Creates a SQL > expression.

Example

let data = users.select(name).filter(id.gt(1));
assert_eq!(Ok("Tess".to_string()), data.first(&connection));

fn ge<T: AsExpression<Self::SqlType>>(self, other: T) -> GtEq<Self, T::Expression>

Creates a SQL >= expression.

Example

let data = users.select(name).filter(id.ge(2));
assert_eq!(Ok("Tess".to_string()), data.first(&connection));

fn lt<T: AsExpression<Self::SqlType>>(self, other: T) -> Lt<Self, T::Expression>

Creates a SQL < expression.

Example

let data = users.select(name).filter(id.lt(2));
assert_eq!(Ok("Sean".to_string()), data.first(&connection));

fn le<T: AsExpression<Self::SqlType>>(self, other: T) -> LtEq<Self, T::Expression>

Creates a SQL <= expression.

Example

let data = users.select(name).filter(id.le(2));
assert_eq!(Ok("Sean".to_string()), data.first(&connection));

fn between<T: AsExpression<Self::SqlType>>(self, other: Range<T>) -> Between<Self, And<T::Expression, T::Expression>>

Creates a SQL BETWEEN expression using the given range.

fn not_between<T: AsExpression<Self::SqlType>>(self, other: Range<T>) -> NotBetween<Self, And<T::Expression, T::Expression>>

Creates a SQL NOT BETWEEN expression using the given range.

fn desc(self) -> Desc<Self>

Creates a SQL DESC expression, representing this expression in descending order.

fn asc(self) -> Asc<Self>

Creates a SQL ASC expression, representing this expression in descending order.

This is the same as leaving the direction unspecified. It is useful if you need to provide an unknown ordering, and need to box the return value of a function.

Example

let ordering: Box<BoxableExpression<users, (), SqlType=()>> =
    if order == "name" {
        Box::new(name.desc())
    } else {
        Box::new(id.asc())
    };

Implementors