Merge branch 'develop' into support-distinct-in-new-engine

sql/src/test/java/com/amazon/opendistroforelasticsearch/sql/sql/antlr/SQLSyntaxParserTest.java

@@ -122,6 +122,16 @@ public void canParseDistinctClause() {
     assertNotNull(parser.parse("SELECT DISTINCT name, balance FROM test"));
   }
 
+  @Test
+  public void canParseCaseStatement() {
+    assertNotNull(parser.parse("SELECT CASE WHEN age > 30 THEN 'age1' ELSE 'age2' END FROM test"));
+    assertNotNull(parser.parse("SELECT CASE WHEN age > 30 THEN 'age1' "
+                                        + " WHEN age < 50 THEN 'age2' "
+                                        + " ELSE 'age3' END FROM test"));
+    assertNotNull(parser.parse("SELECT CASE age WHEN 30 THEN 'age1' ELSE 'age2' END FROM test"));
+    assertNotNull(parser.parse("SELECT CASE age WHEN 30 THEN 'age1' END FROM test"));
+  }
+
   @Test
   public void canNotParseAggregateFunctionWithWrongArgument() {
     assertThrows(SyntaxCheckException.class, () -> parser.parse("SELECT SUM() FROM test"));

sql/src/test/java/com/amazon/opendistroforelasticsearch/sql/sql/parser/AstBuilderTest.java

@@ -455,6 +455,31 @@ public void can_build_select_all_clause() {
     );
   }
 
+  @Test
+  public void can_build_from_subquery() {
+    assertEquals(
+        project(
+            filter(
+                relationSubquery(
+                    project(
+                        relation("test"),
+                        alias("firstname", qualifiedName("firstname"), "first"),
+                        alias("lastname", qualifiedName("lastname"), "last")
+                    ),
+                    "a"
+                ),
+                function(">", qualifiedName("age"), intLiteral(20))
+            ),
+            alias("a.first", qualifiedName("a", "first")),
+            alias("last", qualifiedName("last"))),
+        buildAST(
+            "SELECT a.first, last FROM ("
+                + "SELECT firstname AS first, lastname AS last FROM test"
+                + ") AS a where age > 20"
+        )
+    );
+  }
+
   private UnresolvedPlan buildAST(String query) {
     ParseTree parseTree = parser.parse(query);
     return parseTree.accept(new AstBuilder(query));