Support Enum in SqlTransform

I ran into this problem when trying to put my Avro records through the SqlTransform.

I was able to reduce the reproduction path to the code below.

This code fails on my machine (using Beam 2.19.0) with the following NullPointerException
```

org.apache.beam.sdk.extensions.sql.impl.ParseException: Unable to parse query SELECT name, direction
FROM InputStream at org.apache.beam.sdk.extensions.sql.impl.CalciteQueryPlanner.convertToBeamRel(CalciteQueryPlanner.java:175)
at
org.apache.beam.sdk.extensions.sql.impl.BeamSqlEnv.parseQuery(BeamSqlEnv.java:103)
at org.apache.beam.sdk.extensions.sql.SqlTransform.expand(SqlTransform.java:125)
at
org.apache.beam.sdk.extensions.sql.SqlTransform.expand(SqlTransform.java:83)
at org.apache.beam.sdk.Pipeline.applyInternal(Pipeline.java:539)
at
org.apache.beam.sdk.Pipeline.applyTransform(Pipeline.java:490)
at org.apache.beam.sdk.values.PCollectionTuple.apply(PCollectionTuple.java:261)
at
com.bol.analytics.m2.TestAvro2SQL.testAvro2SQL(TestAvro2SQL.java:99)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native
Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at
java.lang.reflect.Method.invoke(Method.java:498)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
at
org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
at
org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
at org.apache.beam.sdk.testing.TestPipeline$1.evaluate(TestPipeline.java:319)
at
org.junit.rules.RunRules.evaluate(RunRules.java:20)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
at
org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
at
org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
at
org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
at
org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
at org.junit.runners.ParentRunner.run(ParentRunner.java:363)
at
org.junit.runner.JUnitCore.run(JUnitCore.java:137)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
at
com.intellij.rt.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:33)
at com.intellij.rt.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:230)
at
com.intellij.rt.junit.JUnitStarter.main(JUnitStarter.java:58)
Caused by: org.apache.beam.vendor.calcite.v1_20_0.org.apache.calcite.tools.ValidationException:
java.lang.NullPointerException
at org.apache.beam.vendor.calcite.v1_20_0.org.apache.calcite.prepare.PlannerImpl.validate(PlannerImpl.java:217)
at
org.apache.beam.sdk.extensions.sql.impl.CalciteQueryPlanner.convertToBeamRel(CalciteQueryPlanner.java:144)
...
31 more
Caused by: java.lang.NullPointerException
at org.apache.beam.vendor.calcite.v1_20_0.org.apache.calcite.sql.type.SqlTypeFactoryImpl.createSqlType(SqlTypeFactoryImpl.java:45)
at
org.apache.beam.sdk.extensions.sql.impl.utils.CalciteUtils.toRelDataType(CalciteUtils.java:280)
at
org.apache.beam.sdk.extensions.sql.impl.utils.CalciteUtils.toRelDataType(CalciteUtils.java:287)
at
org.apache.beam.sdk.extensions.sql.impl.utils.CalciteUtils.lambda$toCalciteRowType$0(CalciteUtils.java:261)
at
java.util.stream.Streams$RangeIntSpliterator.forEachRemaining(Streams.java:110)
at java.util.stream.IntPipeline$Head.forEach(IntPipeline.java:581)
at
org.apache.beam.sdk.extensions.sql.impl.utils.CalciteUtils.toCalciteRowType(CalciteUtils.java:258)
at
org.apache.beam.sdk.extensions.sql.impl.BeamCalciteTable.getRowType(BeamCalciteTable.java:71)
at org.apache.beam.vendor.calcite.v1_20_0.org.apache.calcite.sql.validate.EmptyScope.resolve_(EmptyScope.java:159)
at
org.apache.beam.vendor.calcite.v1_20_0.org.apache.calcite.sql.validate.EmptyScope.resolveTable(EmptyScope.java:99)
at
org.apache.beam.vendor.calcite.v1_20_0.org.apache.calcite.sql.validate.DelegatingScope.resolveTable(DelegatingScope.java:203)
at
org.apache.beam.vendor.calcite.v1_20_0.org.apache.calcite.sql.validate.IdentifierNamespace.resolveImpl(IdentifierNamespace.java:105)
at
org.apache.beam.vendor.calcite.v1_20_0.org.apache.calcite.sql.validate.IdentifierNamespace.validateImpl(IdentifierNamespace.java:177)
at
org.apache.beam.vendor.calcite.v1_20_0.org.apache.calcite.sql.validate.AbstractNamespace.validate(AbstractNamespace.java:84)
at
org.apache.beam.vendor.calcite.v1_20_0.org.apache.calcite.sql.validate.SqlValidatorImpl.validateNamespace(SqlValidatorImpl.java:995)
at
org.apache.beam.vendor.calcite.v1_20_0.org.apache.calcite.sql.validate.SqlValidatorImpl.validateQuery(SqlValidatorImpl.java:955)
at
org.apache.beam.vendor.calcite.v1_20_0.org.apache.calcite.sql.validate.SqlValidatorImpl.validateFrom(SqlValidatorImpl.java:3109)
at
org.apache.beam.vendor.calcite.v1_20_0.org.apache.calcite.sql.validate.SqlValidatorImpl.validateFrom(SqlValidatorImpl.java:3091)
at
org.apache.beam.vendor.calcite.v1_20_0.org.apache.calcite.sql.validate.SqlValidatorImpl.validateSelect(SqlValidatorImpl.java:3363)
at
org.apache.beam.vendor.calcite.v1_20_0.org.apache.calcite.sql.validate.SelectNamespace.validateImpl(SelectNamespace.java:60)
at
org.apache.beam.vendor.calcite.v1_20_0.org.apache.calcite.sql.validate.AbstractNamespace.validate(AbstractNamespace.java:84)
at
org.apache.beam.vendor.calcite.v1_20_0.org.apache.calcite.sql.validate.SqlValidatorImpl.validateNamespace(SqlValidatorImpl.java:995)
at
org.apache.beam.vendor.calcite.v1_20_0.org.apache.calcite.sql.validate.SqlValidatorImpl.validateQuery(SqlValidatorImpl.java:955)
at
org.apache.beam.vendor.calcite.v1_20_0.org.apache.calcite.sql.SqlSelect.validate(SqlSelect.java:216)
at
org.apache.beam.vendor.calcite.v1_20_0.org.apache.calcite.sql.validate.SqlValidatorImpl.validateScopedExpression(SqlValidatorImpl.java:930)
at
org.apache.beam.vendor.calcite.v1_20_0.org.apache.calcite.sql.validate.SqlValidatorImpl.validate(SqlValidatorImpl.java:637)
at
org.apache.beam.vendor.calcite.v1_20_0.org.apache.calcite.prepare.PlannerImpl.validate(PlannerImpl.java:215)
...
32 more

```

 
```

@Test
@Category(NeedsRunner.class)
public void testAvro2SQL() {
// ============================================================

// The base test input

Schema testSchema = (new Schema.Parser()).parse(

"{\"type\":\"record\",\"name\":\"Transport\"," +
"\"fields\":[" +

"{\"name\":\"name\",\"type\":[\"null\",{\"type\":\"string\",\"avro.java.string\":\"String\"}],\"default\":null},"
+
"{\"name\":\"direction\",\"type\":{\"type\":\"enum\",\"name\":\"DirectionType\",\"symbols\":[\"PULL\",\"PUSH\"]}}"
+
"]}");

GenericRecord record = new GenericRecordBuilder(testSchema)

.set("name", "Test")
.set("direction", new GenericData.EnumSymbol(testSchema.getField("direction").schema(),
"PULL"))
.build();

// List of test Inputs
List testRecords
= Collections.singletonList(record);

// ============================================================

// Convert into a PCollection
PCollection input = pipeline
.apply(Create.of(testRecords).withCoder(AvroGenericCoder.of(testSchema)))

.apply(ParDo.of(new DoFn() {
@ProcessElement

public void processElement(ProcessContext c) {
c.output(toBeamRowStrict(c.element(),
null));
}
}))
.setRowSchema(toBeamSchema(testSchema));

// ============================================================

PCollection result
=
// This way we give a name to the input stream for use in the SQL
PCollectionTuple

.of("InputStream", input)
// Apply the SQL.
.apply("Execute
SQL", SqlTransform
.query("SELECT" +
" name, direction
" +
"FROM InputStream"));

pipeline.run().waitUntilFinish();

}

```

Imported from Jira [BEAM-9361](https://issues.apache.org/jira/browse/BEAM-9361). Original Jira may contain additional context.
Reported by: nielsbasjes.