Exists — Correlated Predicate Subquery Expression¶
Exists is a SubqueryExpression and a predicate expression.
Exists is <
ResolveSubqueryis requested to resolveSubQueries
PullupCorrelatedPredicatesis requested to spark-sql-PullupCorrelatedPredicates.md#rewriteSubQueries[rewriteSubQueries]
AstBuilderis requested to sql/AstBuilder.md#visitExists[visitExists] (in SQL statements)
Exists is unevaluable expression.
[[eval]][[doGenCode]] When requested to evaluate or
Exists simply reports a
Cannot evaluate expression: [this]
Exists is never Expression.md#nullable[nullable].
Exists uses the following text representation:
[[canonicalized]] When requested for a canonicalized version,
Exists takes the following to be created:
- [[plan]] Subquery LogicalPlan
- [[children]] Child Expressions