Struct Pushdown 

pub struct Pushdown {
    pub sql: String,
    pub order_table: Option<String>,
    pub join_left: Option<(String, Vec<String>)>,
}

A pushdown plan: SQL whose execution is provably identical to the Quarb query’s — plus the table whose primary key must order the rows (None for a single aggregate row, where order is moot). The driver appends the ORDER BY, since the key lives in its catalog.

Fields

sql: String

order_table: Option<String>

join_left: Option<(String, Vec<String>)>

Present when the plan contains a witness JOIN: the left table and the left-side columns its ON equalities bind. The plan is only sound if those columns form a unique key of the left table (else SQL multiplies rows where Quarb’s existential binding does not) — the driver must verify against its catalog before executing, and fall back to the scan if it cannot.