org.apache.beam.sdk.extensions.sql.zetasql

Class SqlCoalesceOperatorRewriter

java.lang.Object

org.apache.beam.sdk.extensions.sql.zetasql.SqlCoalesceOperatorRewriter

All Implemented Interfaces:

SqlOperatorRewriter

public class SqlCoalesceOperatorRewriter
extends java.lang.Object
implements SqlOperatorRewriter

Rewrites COALESCE calls as CASE ($case_no_value) calls.

Turns COALESCE(a, b, c) into:

CASE
   WHEN a IS NOT NULL THEN a
   WHEN b IS NOT NULL THEN b
   ELSE c
   END

There is also a special case for the single-argument case: COALESCE(a) becomes just a.

Constructor Summary

Constructors

Constructor and Description
SqlCoalesceOperatorRewriter()

Method Summary

Modifier and Type	Method and Description
org.apache.beam.vendor.calcite.v1_20_0.org.apache.calcite.rex.RexNode	apply(org.apache.beam.vendor.calcite.v1_20_0.org.apache.calcite.rex.RexBuilder rexBuilder, java.util.List<org.apache.beam.vendor.calcite.v1_20_0.org.apache.calcite.rex.RexNode> operands) Create and return a new RexNode that represents a call to this operator with the specified operands.

Methods inherited from class java.lang.Object

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

Constructor Detail

SqlCoalesceOperatorRewriter

public SqlCoalesceOperatorRewriter()

Method Detail

apply

public org.apache.beam.vendor.calcite.v1_20_0.org.apache.calcite.rex.RexNode apply(org.apache.beam.vendor.calcite.v1_20_0.org.apache.calcite.rex.RexBuilder rexBuilder,
                                                                                   java.util.List<org.apache.beam.vendor.calcite.v1_20_0.org.apache.calcite.rex.RexNode> operands)

Description copied from interface: SqlOperatorRewriter

Create and return a new RexNode that represents a call to this operator with the specified operands.

Specified by:

apply in interface SqlOperatorRewriter

Parameters:

rexBuilder - A RexBuilder instance to use for creating new RexNodes

operands - The original list of RexNode operands passed to this operator call

Returns:

The created RexNode