Trait CountQuery 

pub trait CountQuery<Idx> { }

SELECT count(*) over a query’s FROM/JOIN/WHERE/GROUP BY, with its ORDER BY/LIMIT/OFFSET dropped — a total counts the rows that match, not the page being shown. Returns a number rather than an Option, since a count query always produces exactly one row.

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementations on Foreign Types

impl<Output> CountQuery<()> for DynSelect<Postgres, Output>

Erasure is for a query whose joins depend on a condition, and such a query is paged like any other, so it counts like any other. The same goes for a set-operation chain.

impl<Output> CountQuery<()> for SetOp<Postgres, Output>

impl<Scope, Sel: Selection<Scope, Idx>, Idx> CountQuery<Idx> for Select<Postgres, Scope, Sel>

Implementors