Package org.apache.druid.sql.calcite.expression.builtin

Class CoalesceOperatorConversion

java.lang.Object

org.apache.druid.sql.calcite.expression.builtin.CoalesceOperatorConversion

All Implemented Interfaces:

SqlOperatorConversion

public class CoalesceOperatorConversion
extends Object
implements SqlOperatorConversion

Converts SQL COALESCE, NVL, IFNULL to native "coalesce" or "nvl". Native "nvl" is used when there are 2 args, just because it's older and therefore the converted queries have improved backwards-compatibility.

Constructor Summary

Constructors

Constructor	Description
CoalesceOperatorConversion(org.apache.calcite.sql.SqlFunction function)

Method Summary

Modifier and Type	Method	Description
org.apache.calcite.sql.SqlOperator	calciteOperator()	Returns the SQL operator corresponding to this function.
DruidExpression	toDruidExpression(PlannerContext plannerContext, RowSignature rowSignature, org.apache.calcite.rex.RexNode rexNode)	Translate a Calcite RexNode to a Druid expression.
DruidExpression	toDruidExpressionWithPostAggOperands(PlannerContext plannerContext, RowSignature rowSignature, org.apache.calcite.rex.RexNode rexNode, PostAggregatorVisitor postAggregatorVisitor)	Translate a Calcite RexNode to a Druid expression, with the possibility of having postagg operands.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.apache.druid.sql.calcite.expression.SqlOperatorConversion

toDruidFilter, toPostAggregator

Constructor Details

CoalesceOperatorConversion

public CoalesceOperatorConversion(org.apache.calcite.sql.SqlFunction function)

Method Details

calciteOperator

public org.apache.calcite.sql.SqlOperator calciteOperator()

Description copied from interface: SqlOperatorConversion

Returns the SQL operator corresponding to this function. Should be a singleton.

Specified by:

calciteOperator in interface SqlOperatorConversion

Returns:

operator

toDruidExpression

@Nullable
public DruidExpression toDruidExpression(PlannerContext plannerContext,
 RowSignature rowSignature,
 org.apache.calcite.rex.RexNode rexNode)

Description copied from interface: SqlOperatorConversion

Translate a Calcite RexNode to a Druid expression.

Specified by:

toDruidExpression in interface SqlOperatorConversion

Parameters:

plannerContext - SQL planner context

rowSignature - signature of the rows to be extracted from

rexNode - expression meant to be applied on top of the rows

Returns:

Druid expression, or null if translation is not possible

See Also:

• Expressions.toDruidExpression(PlannerContext, RowSignature, RexNode)

toDruidExpressionWithPostAggOperands

@Nullable
public DruidExpression toDruidExpressionWithPostAggOperands(PlannerContext plannerContext,
 RowSignature rowSignature,
 org.apache.calcite.rex.RexNode rexNode,
 PostAggregatorVisitor postAggregatorVisitor)

Description copied from interface: SqlOperatorConversion

Translate a Calcite RexNode to a Druid expression, with the possibility of having postagg operands.

Specified by:

toDruidExpressionWithPostAggOperands in interface SqlOperatorConversion

Parameters:

plannerContext - SQL planner context

rowSignature - signature of the rows to be extracted from

rexNode - expression meant to be applied on top of the rows

postAggregatorVisitor - visitor that manages postagg names and tracks postaggs that were created as by the translation

Returns:

Druid expression, or null if translation is not possible

See Also:

• Expressions.toDruidExpression(PlannerContext, RowSignature, RexNode)