Struct W 

pub struct W<'inner, 'outer> { /* private fields */ }

A struct allowing insertion of window functions

Lifetimes

The 'inner lifetime represents the lifetime of the query you are starting with. The 'outer lifetime represents the lifetime of the the new query containing the window function expressions.

Ideally this would not be used and you would just use something like Expr::row_number().over(...), but the query builder being used requires that PARTITION BY takes only column names, therefore to support any arbitrary expression we need to place everything into a subquery in which we just alias all expressions to single tables.

If you have a table in the 'inner scope, you can freely use W::id to bring it to 'outer.

Implementations

impl<'inner, 'outer> W<'inner, 'outer>

pub fn row_number(&mut self, over: Over<'inner>) -> Expr<'outer, i64>

pub fn rank(&mut self, over: Over<'inner>) -> Expr<'outer, i64>

pub fn dense_rank(&mut self, over: Over<'inner>) -> Expr<'outer, i64>

pub fn percent_rank(&mut self, over: Over<'inner>) -> Expr<'outer, f64>

pub fn cume_dist(&mut self, over: Over<'inner>) -> Expr<'outer, f64>

pub fn ntile( &mut self, num_buckets: Expr<'outer, i64>, over: Over<'inner>, ) -> Expr<'outer, f64>

pub fn lag<T: Table<'inner> + ForLifetimeTable>( &mut self, value: T, offset: Option<Expr<'outer, i64>>, default: Option<T>, over: Over<'inner>, ) -> T::WithLt<'outer>

pub fn lead<T: Table<'inner> + ForLifetimeTable>( &mut self, value: T, offset: Option<Expr<'outer, i64>>, default: Option<T>, over: Over<'inner>, ) -> T::WithLt<'outer>

pub fn first_value<T: Table<'inner> + ForLifetimeTable>( &mut self, value: T, over: Over<'inner>, ) -> T::WithLt<'outer>

pub fn last_value<T: Table<'inner> + ForLifetimeTable>( &mut self, value: T, over: Over<'inner>, ) -> T::WithLt<'outer>

pub fn id<T: Table<'inner> + ForLifetimeTable>( &mut self, table: T, ) -> T::WithLt<'outer>

Bring a table in the 'inner scope to the 'outer scope.

Ideally this wouldn’t be needed, but the sql builder used internally doesn’t support arbitrary expressions in window function partitions, so we have to move everything into a subquery. This function is then used to reselect the input table from this subquery.