Github user chunhui-shi commented on a diff in the pull request:
https://github.com/apache/drill/pull/1224#discussion_r185159367
--- Diff:
exec/java-exec/src/main/java/org/apache/drill/exec/planner/sql/DrillConformance.java
---
@@ -0,0 +1,43 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.drill.exec.planner.sql;
+
+import org.apache.calcite.sql.validate.SqlConformanceEnum;
+import org.apache.calcite.sql.validate.SqlDelegatingConformance;
+
+/**
+ * Drill's SQL conformance is SqlConformanceEnum.DEFAULT except for method
isApplyAllowed().
+ * Since Drill is going to allow OUTER APPLY and CROSS APPLY to allow each
row from left child of Join
+ * to join with output of right side (sub-query or table function that
will be invoked for each row).
+ * Refer to DRILL-5999 for more information.
+ */
+public class DrillConformance extends SqlDelegatingConformance {
--- End diff --
I think DrillConformance should be an independent class since we rely on
this class to define the conformance used in Drill and we might add something
more in the future to enable some other syntax. Let me know if this answer your
suggestion.
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