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

Class SqlCaseWithValueOperatorRewriter

java.lang.Object

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

All Implemented Interfaces:

SqlOperatorRewriter

public class SqlCaseWithValueOperatorRewriter
extends java.lang.Object
implements SqlOperatorRewriter

Rewrites $case_with_value calls as $case_no_value calls.

Turns:

CASE x
   WHEN w1 THEN t1
   WHEN w2 THEN t2
   ELSE e
   END

into:

CASE
   WHEN x == w1 THEN t1
   WHEN x == w2 THEN t2
   ELSE expr
   END

Note that the ELSE statement is actually optional, but we don't need to worry about that here because the ZetaSQL analyzer populates the ELSE argument as a NULL literal if it's not specified.

Constructor Summary

Constructors

Constructor and Description
SqlCaseWithValueOperatorRewriter()

Method Summary

Modifier and Type	Method and Description
org.apache.calcite.rex.RexNode	apply(org.apache.calcite.rex.RexBuilder rexBuilder, java.util.List<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

SqlCaseWithValueOperatorRewriter

public SqlCaseWithValueOperatorRewriter()

Method Detail

apply

public org.apache.calcite.rex.RexNode apply(org.apache.calcite.rex.RexBuilder rexBuilder,
                                            java.util.List<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