Github user hvanhovell commented on a diff in the pull request:
https://github.com/apache/spark/pull/16954#discussion_r103340692
--- Diff:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/subquery.scala
---
@@ -40,19 +42,179 @@ abstract class PlanExpression[T <: QueryPlan[_]]
extends Expression {
/**
* A base interface for expressions that contain a [[LogicalPlan]].
*/
-abstract class SubqueryExpression extends PlanExpression[LogicalPlan] {
+abstract class SubqueryExpression(
+ plan: LogicalPlan,
+ children: Seq[Expression],
+ exprId: ExprId) extends PlanExpression[LogicalPlan] {
+
+ override lazy val resolved: Boolean = childrenResolved && plan.resolved
+ override lazy val references: AttributeSet =
+ if (plan.resolved) super.references -- plan.outputSet else
super.references
override def withNewPlan(plan: LogicalPlan): SubqueryExpression
+ override def semanticEquals(o: Expression): Boolean = o match {
+ case p: SubqueryExpression =>
+ this.getClass.getName.equals(p.getClass.getName) &&
plan.sameResult(p.plan) &&
+ children.length == p.children.length &&
+ children.zip(p.children).forall(p => p._1.semanticEquals(p._2))
+ case _ => false
+ }
}
object SubqueryExpression {
+ /**
+ * Returns true when an expression contains an IN or EXISTS subquery and
false otherwise.
+ */
+ def hasInOrExistsSubquery(e: Expression): Boolean = {
+ e.find {
+ case _: ListQuery | _: Exists => true
+ case _ => false
+ }.isDefined
+ }
+
+ /**
+ * Returns true when an expression contains a subquery that has outer
reference(s). The outer
+ * reference attributes are kept as children of subquery expression by
+ * [[org.apache.spark.sql.catalyst.analysis.Analyzer.ResolveSubquery]]
+ */
def hasCorrelatedSubquery(e: Expression): Boolean = {
e.find {
- case e: SubqueryExpression if e.children.nonEmpty => true
+ case s: SubqueryExpression if s.children.nonEmpty => true
case _ => false
}.isDefined
}
}
+object SubExprUtils extends PredicateHelper {
+ /**
+ * Returns true when an expression contains correlated predicates i.e
outer references and
+ * returns false otherwise.
+ */
+ def containsOuter(e: Expression): Boolean = {
+ e.find(_.isInstanceOf[OuterReference]).isDefined
+ }
+
+ /**
+ * Returns whether there are any null-aware predicate subqueries inside
Not. If not, we could
+ * turn the null-aware predicate into not-null-aware predicate.
+ */
+ def hasNullAwarePredicateWithinNot(e: Expression): Boolean = {
+ e.find{ x =>
+ x.isInstanceOf[Not] && e.find {
--- End diff --
I am pretty sure this is wrong. This will work on the following expression:
`NOT(a) AND b IN(SELECT q FROM t)`
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