SubqueryExpression Expressions

Author: jaceklaskowski

docs/expressions/SubqueryExpression.md

@@ -1,12 +1,36 @@
+---
+title: SubqueryExpression
+---
+
 # SubqueryExpression Expressions
 
 `SubqueryExpression` is an [extension](#contract) of the [PlanExpression](PlanExpression.md) abstraction for [subquery expressions](#implementations) with [logical plans](#plan) (for a subquery).
 
 ## Contract
 
-### withNewPlan
+## hint
+
+```scala
+hint: Option[HintInfo]
+```
+
+Used when:
+
+* [EliminateResolvedHint](../logical-optimizations/EliminateResolvedHint.md) logical optimization is executed (and [pullHintsIntoSubqueries](../logical-optimizations/EliminateResolvedHint.md#pullHintsIntoSubqueries))
+
+## withNewHint { #withNewHint }
+
+```scala
+withNewHint(
+  hint: Option[HintInfo]): SubqueryExpression
+```
+
+Used when:
+
+* [EliminateResolvedHint](../logical-optimizations/EliminateResolvedHint.md) logical optimization is executed (and [pullHintsIntoSubqueries](../logical-optimizations/EliminateResolvedHint.md#pullHintsIntoSubqueries))
+
+### withNewPlan { #withNewPlan }
 
- <span id="withNewPlan">
 ```scala
 withNewPlan(
   plan: LogicalPlan): SubqueryExpression
@@ -25,6 +49,7 @@ withNewPlan(
 
 * [DynamicPruningSubquery](DynamicPruningSubquery.md)
 * [Exists](Exists.md)
+* `LateralSubquery`
 * [ListQuery](ListQuery.md)
 * [ScalarSubquery](ScalarSubquery.md)
 
@@ -33,73 +58,99 @@ withNewPlan(
 `SubqueryExpression` takes the following to be created:
 
 * <span id="plan"> [Subquery logical plan](../logical-operators/LogicalPlan.md)
-* <span id="children"> Child [Expressions](Expression.md)
+* <span id="outerAttrs"> Outer Attributes ([Expression](Expression.md)s)
 * <span id="exprId"> Expression ID
+* <span id="joinCond"> Join Condition ([Expression](Expression.md)s)
+* <span id="hint"> [HintInfo](../hints/HintInfo.md)
 
 !!! note "Abstract Class"
     `SubqueryExpression` is an abstract class and cannot be created directly. It is created indirectly for the [concrete SubqueryExpressions](#implementations).
 
 ## References
 
-<span id="references">
-```scala
-references: AttributeSet
-```
+??? note "Expression"
+
+    ```scala
+    references: AttributeSet
+    ```
+
+    `references` is part of the [Expression](Expression.md#references) abstraction.
 
 `references` is...FIXME
 
-`references` is part of the [Expression](Expression.md#references) abstraction.
+## resolved
 
-## resolved Predicate
+??? note "Expression"
 
-<span id="resolved">
-```scala
-resolved: Boolean
-```
+    ```scala
+    resolved: Boolean
+    ```
+
+    `resolved` is part of the [Expression](Expression.md#resolved) abstraction.
 
 `resolved` is `true` when all of the following hold:
 
 * [children are all resolved](Expression.md#childrenResolved)
 * [subquery logical plan](#plan) is [resolved](../logical-operators/LogicalPlan.md#resolved)
 
-`resolved` is part of the [Expression](Expression.md#resolved) abstraction.
-
-## hasInOrCorrelatedExistsSubquery Utility
+## hasInOrCorrelatedExistsSubquery { #hasInOrCorrelatedExistsSubquery }
 
-<span id="hasInOrCorrelatedExistsSubquery">
 ```scala
 hasInOrCorrelatedExistsSubquery(
   e: Expression): Boolean
 ```
 
 `hasInOrCorrelatedExistsSubquery`...FIXME
 
-`hasInOrCorrelatedExistsSubquery` is used when [RewritePredicateSubquery](../logical-optimizations/RewritePredicateSubquery.md) logical optimization is executed.
+---
+
+`hasInOrCorrelatedExistsSubquery` is used when:
+
+* [RewritePredicateSubquery](../logical-optimizations/RewritePredicateSubquery.md) logical optimization is executed
 
-## hasCorrelatedSubquery Utility
+## hasCorrelatedSubquery { #hasCorrelatedSubquery }
 
-<span id="hasCorrelatedSubquery">
 ```scala
 hasCorrelatedSubquery(
   e: Expression): Boolean
 ```
 
-`hasCorrelatedSubquery`...FIXME
+`hasCorrelatedSubquery` is `true` when the given [Expression](Expression.md) contains a correlated subquery (there is a `SubqueryExpression` with [isCorrelated](#isCorrelated) flag enabled).
+
+!!! note "Correlated Subquery"
+    **Correlated Subquery** is a subquery with outer references.
+
+---
 
 `hasCorrelatedSubquery` is used when:
 
+* [CombineUnions](../logical-optimizations/CombineUnions.md) logical optimization is executed
 * `EliminateOuterJoin` logical optimization is executed
+* `OptimizeOneRowRelationSubquery` logical optimization is executed
 * `Subquery` is created (from an expression)
 * `Filter` logical operator is requested for `validConstraints`
 
-## hasSubquery Utility
+## hasSubquery { #hasSubquery }
 
-<span id="hasSubquery">
 ```scala
 hasSubquery(
   e: Expression): Boolean
 ```
 
-`hasSubquery`...FIXME
+`hasSubquery` is `true` when the given [Expression](Expression.md) contains a subquery (there is a `SubqueryExpression`).
+
+## isCorrelated { #isCorrelated }
+
+```scala
+isCorrelated: Boolean
+```
+
+`isCorrelated` is `true` when there is at least one outer attribute (among the [outerAttrs](#outerAttrs)).
+
+---
+
+`isCorrelated` is used when:
 
-`hasSubquery` is used when...FIXME
+* `SubqueryExpression` is requested to [hasInOrCorrelatedExistsSubquery](#hasInOrCorrelatedExistsSubquery), [hasCorrelatedSubquery](#hasCorrelatedSubquery)
+* `ScalarSubquery` is requested to [hasCorrelatedScalarSubquery](ScalarSubquery.md#hasCorrelatedScalarSubquery)
+* `MergeScalarSubqueries` logical optimization is executed