chen remove the check for implicit join

Signed-off-by: Jialiang Liang <jiallian@amazon.com>

Author: RyanL1997

legacy/src/main/java/org/opensearch/sql/legacy/antlr/visitor/AntlrSqlParseTreeVisitor.java

@@ -290,21 +290,6 @@ public Boolean visitTableSourceBase(TableSourceBaseContext ctx) {
             return !ctx.joinPart().isEmpty();
           }
 
-          @Override
-          public Boolean visitTableSources(TableSourcesContext ctx) {
-            if (ctx.tableSource().size() > 1) {
-              return true;
-            }
-
-            for (int i = 0; i < ctx.tableSource().size(); i++) {
-              Boolean hasJoinInTableSource = visit(ctx.tableSource(i));
-              if (hasJoinInTableSource != null && hasJoinInTableSource) {
-                return true;
-              }
-            }
-            return false;
-          }
-
           @Override
           protected Boolean defaultResult() {
             return false;

legacy/src/test/java/org/opensearch/sql/legacy/antlr/visitor/AntlrSqlParseTreeVisitorTest.java

@@ -107,13 +107,6 @@ public void visitFunctionAsAggregatorShouldThrowException() {
     visit("SELECT max(abs(age)) FROM test");
   }
 
-  @Test
-  public void visitImplicitJoinWithGroupByShouldThrowException() {
-    exceptionRule.expect(RuntimeException.class);
-    exceptionRule.expectMessage("JOIN queries do not support aggregations on the joined result.");
-    visit("SELECT COUNT(*) FROM testIndex t1, testIndex t2 WHERE t1.id = t2.id GROUP BY t1.field");
-  }
-
   @Test
   public void visitExplicitJoinWithGroupByShouldThrowException() {
     exceptionRule.expect(RuntimeException.class);