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org.apache.spark.sql.catalyst.analysis

ResolveLateralColumnAliasReference

object ResolveLateralColumnAliasReference extends Rule[LogicalPlan]

This rule is the second phase to resolve lateral column alias.

Resolve lateral column alias, which references the alias defined previously in the SELECT list. Plan-wise, it handles two types of operators: Project and Aggregate. - in Project, pushing down the referenced lateral alias into a newly created Project, resolve the attributes referencing these aliases - in Aggregate, inserting the Project node above and falling back to the resolution of Project.

The whole process is generally divided into two phases: 1) recognize resolved lateral alias, wrap the attributes referencing them with LateralColumnAliasReference 2) when the whole operator is resolved, or contains Window but have all other resolved, For Project, it unwrap LateralColumnAliasReference, further resolves the attributes and push down the referenced lateral aliases. For Aggregate, it goes through the whole aggregation list, extracts the aggregation expressions and grouping expressions to keep them in this Aggregate node, and add a Project above with the original output. It doesn't do anything on LateralColumnAliasReference, but completely leave it to the Project in the future turns of this rule.

** Example for Project: Before rewrite: Project [age AS a, 'a + 1] +- Child

After phase 1: Project [age AS a, lca(a) + 1] +- Child

After phase 2: Project [a, a + 1] +- Project [child output, age AS a] +- Child

** Example for Aggregate: Before rewrite: Aggregate [dept#14] [dept#14 AS a#12, 'a + 1, avg(salary#16) AS b#13, 'b + avg(bonus#17)] +- Child [dept#14,name#15,salary#16,bonus#17]

After phase 1: Aggregate [dept#14] [dept#14 AS a#12, lca(a) + 1, avg(salary#16) AS b#13, lca(b) + avg(bonus#17)] +- Child [dept#14,name#15,salary#16,bonus#17]

After phase 2: Project [dept#14 AS a#12, lca(a) + 1, avg(salary)#26 AS b#13, lca(b) + avg(bonus)#27] +- Aggregate [dept#14] [avg(salary#16) AS avg(salary)#26, avg(bonus#17) AS avg(bonus)#27,dept#14] +- Child [dept#14,name#15,salary#16,bonus#17]

Now the problem falls back to the lateral alias resolution in Project. After future rounds of this rule: Project [a#12, a#12 + 1, b#13, b#13 + avg(bonus)#27] +- Project [dept#14 AS a#12, avg(salary)#26 AS b#13] +- Aggregate [dept#14] [avg(salary#16) AS avg(salary)#26, avg(bonus#17) AS avg(bonus)#27, dept#14] +- Child [dept#14,name#15,salary#16,bonus#17]

** Example for Window: Query: select dept as d, sum(salary) as s, avg(s) over (partition by s order by d) as avg from employee group by dept

After phase 1: 'Aggregate [dept#17], [dept#17 AS d#15, sum(salary#19) AS s#16L, avg(lca(s#16L)) windowspecdefinition(lca(s#16L), lca(d#15) ASC NULLS FIRST, specifiedwindowframe(..)) AS avg#25] +- Relation spark_catalog.default.employee[dept#17,name#18,salary#19,bonus#20,properties#21] It is similar to a regular Aggregate. All expressions in it are resolved, but itself is unresolved due to the Window expression. The rule allows appliction on this case.

After phase 2: 'Project [dept#17 AS d#15, sum(salary)#26L AS s#16L, avg(lca(s#16L)) windowspecdefinition(lca(s#16L), lca(d#15) ASC NULLS FIRST, specifiedwindowframe(..)) AS avg#25] +- Aggregate [dept#17], [dept#17, sum(salary#19) AS sum(salary)#26L] +- Relation spark_catalog.default.employee[dept#17,name#18,salary#19,bonus#20,properties#21] Same as Aggregate, it extracts grouping expressions and aggregate functions. Window expressions are completely lifted up to upper Project, free from the current Aggregate.

Then this rule will apply on the Project, adding another Project below. Till this phase, all lateral column alias references have been resolved and removed. Finally, rule ExtractWindowExpressions will apply on the top Project with window expressions. It is guaranteed that ResolveLateralColumnAliasReference is applied before ExtractWindowExpressions.

Linear Supertypes
Rule[LogicalPlan], Logging, SQLConfHelper, AnyRef, Any
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  1. ResolveLateralColumnAliasReference
  2. Rule
  3. Logging
  4. SQLConfHelper
  5. AnyRef
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Type Members

  1. case class AliasEntry(alias: Alias, index: Int) extends Product with Serializable

Value Members

  1. final def !=(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  2. final def ##(): Int
    Definition Classes
    AnyRef → Any
  3. final def ==(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  4. def apply(plan: LogicalPlan): LogicalPlan
    Definition Classes
    ResolveLateralColumnAliasReference → Rule
  5. final def asInstanceOf[T0]: T0
    Definition Classes
    Any
  6. def clone(): AnyRef
    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws( ... ) @native()
  7. def conf: SQLConf

    The active config object within the current scope.

    The active config object within the current scope. See SQLConf.get for more information.

    Definition Classes
    SQLConfHelper
  8. final def eq(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  9. def equals(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  10. def finalize(): Unit
    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws( classOf[java.lang.Throwable] )
  11. final def getClass(): Class[_]
    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  12. def hashCode(): Int
    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  13. def initializeLogIfNecessary(isInterpreter: Boolean, silent: Boolean): Boolean
    Attributes
    protected
    Definition Classes
    Logging
  14. def initializeLogIfNecessary(isInterpreter: Boolean): Unit
    Attributes
    protected
    Definition Classes
    Logging
  15. final def isInstanceOf[T0]: Boolean
    Definition Classes
    Any
  16. def isTraceEnabled(): Boolean
    Attributes
    protected
    Definition Classes
    Logging
  17. def log: Logger
    Attributes
    protected
    Definition Classes
    Logging
  18. def logDebug(msg: ⇒ String, throwable: Throwable): Unit
    Attributes
    protected
    Definition Classes
    Logging
  19. def logDebug(msg: ⇒ String): Unit
    Attributes
    protected
    Definition Classes
    Logging
  20. def logError(msg: ⇒ String, throwable: Throwable): Unit
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    protected
    Definition Classes
    Logging
  21. def logError(msg: ⇒ String): Unit
    Attributes
    protected
    Definition Classes
    Logging
  22. def logInfo(msg: ⇒ String, throwable: Throwable): Unit
    Attributes
    protected
    Definition Classes
    Logging
  23. def logInfo(msg: ⇒ String): Unit
    Attributes
    protected
    Definition Classes
    Logging
  24. def logName: String
    Attributes
    protected
    Definition Classes
    Logging
  25. def logTrace(msg: ⇒ String, throwable: Throwable): Unit
    Attributes
    protected
    Definition Classes
    Logging
  26. def logTrace(msg: ⇒ String): Unit
    Attributes
    protected
    Definition Classes
    Logging
  27. def logWarning(msg: ⇒ String, throwable: Throwable): Unit
    Attributes
    protected
    Definition Classes
    Logging
  28. def logWarning(msg: ⇒ String): Unit
    Attributes
    protected
    Definition Classes
    Logging
  29. final def ne(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  30. final def notify(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native()
  31. final def notifyAll(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native()
  32. lazy val ruleId: RuleId
    Attributes
    protected
    Definition Classes
    Rule
  33. val ruleName: String

    Name for this rule, automatically inferred based on class name.

    Name for this rule, automatically inferred based on class name.

    Definition Classes
    Rule
  34. final def synchronized[T0](arg0: ⇒ T0): T0
    Definition Classes
    AnyRef
  35. def toString(): String
    Definition Classes
    AnyRef → Any
  36. final def wait(): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  37. final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )
  38. final def wait(arg0: Long): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws( ... ) @native()

Inherited from Rule[LogicalPlan]

Inherited from Logging

Inherited from SQLConfHelper

Inherited from AnyRef

Inherited from Any

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