Github user dilipbiswal commented on a diff in the pull request:
https://github.com/apache/spark/pull/16954#discussion_r105778315
--- Diff:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/subquery.scala
---
@@ -40,19 +43,189 @@ 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 => s.children.nonEmpty
case _ => false
}.isDefined
}
}
+object SubExprUtils extends PredicateHelper {
--- End diff --
@hvanhovell Actually @nsyca and i had discussed a bit about this.
SubqueryExpression object has methods that operates strictly in the context of
SubqueryExpression where as the utils has methods that mostly deals with
OuterReferences.. So they can operate on the subquery plans referred to from
SubqueryExpression or may be in the future if we support queries of the form.
```
select * from t1 left outer join (select * from t2 where t2.c1 = t1.c1) on
â¦
```
If you think we should merge this two then let me know and i will do it
:-).
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