io.druid.sql.calcite.expression

Interface ExpressionConversion

All Known Implementing Classes:

AbstractExpressionConversion, CharLengthExpressionConversion, ExtractExpressionConversion, FloorExpressionConversion, SubstringExpressionConversion

public interface ExpressionConversion

Method Summary

Modifier and Type	Method and Description
RowExtraction	convert(ExpressionConverter converter, PlannerContext plannerContext, List<String> rowOrder, org.apache.calcite.rex.RexNode expression) Translate a row-expression to a Druid column reference.
String	operatorName() Operator name, if sqlKind() is OTHER_FUNCTION.
org.apache.calcite.sql.SqlKind	sqlKind() SQL kind that this converter knows how to convert.

Method Detail

sqlKind

org.apache.calcite.sql.SqlKind sqlKind()

SQL kind that this converter knows how to convert.

Returns:

sql kind

operatorName

String operatorName()

Operator name, if sqlKind() is OTHER_FUNCTION.

Returns:

operator name, or null

convert

RowExtraction convert(ExpressionConverter converter,
                      PlannerContext plannerContext,
                      List<String> rowOrder,
                      org.apache.calcite.rex.RexNode expression)

Translate a row-expression to a Druid column reference. Note that this signature will probably need to change once we support extractions from multiple columns.

Parameters:

converter - converter that can be used to convert sub-expressions

plannerContext - SQL planner context

rowOrder - order of fields in the Druid rows to be extracted from

expression - expression meant to be applied on top of the table

Returns:

(columnName, extractionFn) or null