SqlToRelConverter.AggConverter

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org.eigenbase.sql2rel
Class SqlToRelConverter.AggConverter

java.lang.Object
  org.eigenbase.sql2rel.SqlToRelConverter.AggConverter

All Implemented Interfaces:: SqlVisitor<Void>

Enclosing class:: SqlToRelConverter

protected class SqlToRelConverter.AggConverter
extends Object
implements SqlVisitor<Void>
extends Object
implements SqlVisitor<Void>

Converts expressions to aggregates.

Consider the expression SELECT deptno, SUM(2 * sal) FROM emp GROUP BY deptno Then

groupExprs = {SqlIdentifier(deptno)}
convertedInputExprs = {RexInputRef(deptno), 2 * RefInputRef(sal)}
inputRefs = {RefInputRef(#0), RexInputRef(#1)}
aggCalls = {AggCall(SUM, {1})}

Field Summary
`private Map<AggregateCall,RexNode>`	`aggCallMapping`
`private List<AggregateCall>`	`aggCalls`
`private Map<SqlNode,RexNode>`	`aggMapping`
`private SqlToRelConverter.Blackboard`	`bb`
`private List<String>`	`convertedInputExprNames` Names of `convertedInputExprs`, where the expressions are simple mappings to input fields.
`private List<RexNode>`	`convertedInputExprs` Input expressions for the group columns and aggregates, in `RexNode` format.
`private SqlNodeList`	`groupExprs` The group-by expressions, in `SqlNode` format.
`private List<RexInputRef>`	`inputRefs`
`private Map<String,String>`	`nameMap`

Constructor Summary
`SqlToRelConverter.AggConverter(SqlToRelConverter.Blackboard bb, SqlSelect select)` Creates an AggConverter.

Method Summary
`private void`	`addExpr(RexNode expr, String name)` Adds an expression, deducing an appropriate name if possible.
`void`	`addGroupExpr(SqlNode expr)`
`List<AggregateCall>`	`getAggCalls()`
`List<RexNode>`	`getPreExprs()`
`List<String>`	`getPreNames()`
`RelDataTypeFactory`	`getTypeFactory()`
`RexNode`	`lookupAggregates(SqlCall call)`
`RexNode`	`lookupGroupExpr(SqlNode expr)` If an expression is structurally identical to one of the group-by expressions, returns a reference to the expression, otherwise returns null.
`private int`	`lookupOrCreateGroupExpr(RexNode expr)`
`Void`	`visit(SqlCall call)` Visits a call to a `SqlOperator`.
`Void`	`visit(SqlDataTypeSpec type)` Visits a datatype specification.
`Void`	`visit(SqlDynamicParam param)` Visits a dynamic parameter.
`Void`	`visit(SqlIdentifier id)` Visits an identifier.
`Void`	`visit(SqlIntervalQualifier intervalQualifier)` Visits an interval qualifier
`Void`	`visit(SqlLiteral lit)` Visits a literal.
`Void`	`visit(SqlNodeList nodeList)` Visits a list of `SqlNode` objects.

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Field Detail

bb

private final SqlToRelConverter.Blackboard bb

nameMap

private final Map<String,String> nameMap

groupExprs

private final SqlNodeList groupExprs

The group-by expressions, in SqlNode format.

convertedInputExprs

private final List<RexNode> convertedInputExprs

Input expressions for the group columns and aggregates, in RexNode format. The first elements of the list correspond to the elements in groupExprs; the remaining elements are for aggregates.

convertedInputExprNames

private final List<String> convertedInputExprNames

Names of convertedInputExprs, where the expressions are simple mappings to input fields.

inputRefs

private final List<RexInputRef> inputRefs

aggCalls

private final List<AggregateCall> aggCalls

aggMapping

private final Map<SqlNode,RexNode> aggMapping

aggCallMapping

private final Map<AggregateCall,RexNode> aggCallMapping

Constructor Detail

SqlToRelConverter.AggConverter

public SqlToRelConverter.AggConverter(SqlToRelConverter.Blackboard bb,
                                      SqlSelect select)

Creates an AggConverter.

The select parameter provides enough context to name aggregate calls which are top-level select list items.

Parameters:: bb - Blackboard; select - Query being translated; provides context to give

Method Detail

addGroupExpr

public void addGroupExpr(SqlNode expr)

addExpr

private void addExpr(RexNode expr,
                     String name)

Adds an expression, deducing an appropriate name if possible.

Parameters:: expr - Expression; name - Suggested name