Make Coral IR friendly to missng table alias prefix

coral-common/src/main/java/com/linkedin/coral/common/CoralJavaTypeFactoryImpl.java

@@ -0,0 +1,21 @@
+package com.linkedin.coral.common;
+
+import org.apache.calcite.jdbc.JavaTypeFactoryImpl;
+import org.apache.calcite.rel.type.RelDataType;
+import org.apache.calcite.rel.type.RelDataTypeSystem;
+import org.apache.calcite.rel.type.StructKind;
+
+import java.util.List;
+
+public class CoralJavaTypeFactoryImpl extends JavaTypeFactoryImpl {
+    public CoralJavaTypeFactoryImpl(RelDataTypeSystem typeSystem) {
+        super(typeSystem);
+    }
+
+    @Override
+    public RelDataType createStructType(
+            final List<RelDataType> typeList,
+            final List<String> fieldNameList) {
+        return createStructType(StructKind.PEEK_FIELDS, typeList, fieldNameList);
+    }
+}

coral-common/src/main/java/com/linkedin/coral/common/HiveCommonRelBuilder.java

@@ -0,0 +1,22 @@
+package com.linkedin.coral.common;
+
+import org.apache.calcite.plan.Context;
+import org.apache.calcite.plan.RelOptCluster;
+import org.apache.calcite.plan.RelOptSchema;
+import org.apache.calcite.rex.RexBuilder;
+import org.apache.calcite.tools.FrameworkConfig;
+import org.apache.calcite.tools.Frameworks;
+import org.apache.calcite.tools.RelBuilder;
+
+public class HiveCommonRelBuilder extends RelBuilder {
+    private HiveCommonRelBuilder(Context context, RelOptCluster cluster, RelOptSchema relOptSchema) {
+        super(context, cluster, relOptSchema);
+    }
+
+    public static RelBuilder create(FrameworkConfig config) {
+        return Frameworks.withPrepare(config, (cluster, relOptSchema, rootSchema,
+                statement) -> { cluster = RelOptCluster.create(cluster.getPlanner(),
+                new RexBuilder(new CoralJavaTypeFactoryImpl(cluster.getTypeFactory().getTypeSystem())));
+                return new HiveCommonRelBuilder(config.getContext(), cluster, relOptSchema);});
+    }
+}

coral-common/src/main/java/com/linkedin/coral/common/ToRelConverter.java

@@ -170,7 +170,7 @@ protected RelBuilder getRelBuilder() {
     // 2. Converted expression is harder to validate for correctness(because it appears different from input)
     if (relBuilder == null) {
       Hook.REL_BUILDER_SIMPLIFY.add(Hook.propertyJ(false));
-      relBuilder = RelBuilder.create(config);
+      relBuilder = HiveCommonRelBuilder.create(config);
     }
     return relBuilder;
   }

coral-trino/src/test/java/com/linkedin/coral/trino/rel2trino/HiveToTrinoConverterTest.java

@@ -848,4 +848,16 @@ public void testSqlSelectAliasAppenderTransformer() {
         + "WHERE \"tablea\".\"a\" > 5";
     assertEquals(expandedSql, expected);
   }
+
+  @Test
+  public void testSqlSelectAliasAppenderTransformerWithoutTableAlias() {
+    // test.tableA(a int, b struct<b1:string>
+    RelNode relNode = TestUtils.getHiveToRelConverter().convertSql("SELECT b.b1 FROM test.tableA where a > 5");
+    RelToTrinoConverter relToTrinoConverter = TestUtils.getRelToTrinoConverter();
+    String expandedSql = relToTrinoConverter.convert(relNode);
+
+    String expected = "SELECT \"tablea\".\"b\".\"b1\" AS \"b1\"\n" + "FROM \"test\".\"tablea\" AS \"tablea\"\n"
+            + "WHERE \"tablea\".\"a\" > 5";
+    assertEquals(expandedSql, expected);
+  }
 }