Struct SubqueryNormalizer 

pub struct SubqueryNormalizer;

Flattens doubly-nested Select subqueries.

A doubly-nested subquery is:

SELECT … WHERE {
  {
    SELECT … WHERE {
      {
        SELECT … WHERE { … }   ← this innermost is merged up
      }
    }
  }
}

The normalizer merges the innermost Select into its parent when the parent has no patterns or filters of its own and the vars are compatible.

Implementations

impl SubqueryNormalizer

pub fn new() -> Self

Create a new normalizer.

pub fn normalize(&self, node: SubqueryNode) -> SubqueryNode

Normalize node, returning an equivalent (possibly simplified) SubqueryNode.

Trait Implementations

impl Default for SubqueryNormalizer

fn default() -> Self

Returns the “default value” for a type.