diff --git a/core/src/main/java/org/apache/calcite/sql2rel/SqlToRelConverter.java b/core/src/main/java/org/apache/calcite/sql2rel/SqlToRelConverter.java
index e9b9eff95e45..358613196af8 100644
--- a/core/src/main/java/org/apache/calcite/sql2rel/SqlToRelConverter.java
+++ b/core/src/main/java/org/apache/calcite/sql2rel/SqlToRelConverter.java
@@ -6474,7 +6474,8 @@ private class JsonFunctionRexRewriter extends RexShuttle {
     }
 
     @Override public RexNode visitCall(RexCall call) {
-      if (call.getOperator() == SqlStdOperatorTable.JSON_OBJECT) {
+      if (call.getOperator().getName().equals(SqlStdOperatorTable.JSON_OBJECT.getName())
+          && call.getOperator().getKind() == SqlStdOperatorTable.JSON_OBJECT.getKind()) {
         final ImmutableList.Builder<RexNode> builder = ImmutableList.builder();
         for (int i = 0; i < call.operands.size(); ++i) {
           if ((i & 1) == 0 && i != 0) {
@@ -6485,7 +6486,8 @@ private class JsonFunctionRexRewriter extends RexShuttle {
         }
         return rexBuilder.makeCall(SqlStdOperatorTable.JSON_OBJECT, builder.build());
       }
-      if (call.getOperator() == SqlStdOperatorTable.JSON_ARRAY) {
+      if (call.getOperator().getName().equals(SqlStdOperatorTable.JSON_ARRAY.getName())
+          && call.getOperator().getKind() == SqlStdOperatorTable.JSON_ARRAY.getKind()) {
         final ImmutableList.Builder<RexNode> builder = ImmutableList.builder();
         builder.add(call.operands.get(0));
         for (int i = 1; i < call.operands.size(); ++i) {
diff --git a/core/src/test/resources/sql/agg.iq b/core/src/test/resources/sql/agg.iq
index 8541f46ba5f4..f1513ed7de1a 100644
--- a/core/src/test/resources/sql/agg.iq
+++ b/core/src/test/resources/sql/agg.iq
@@ -3777,5 +3777,22 @@ select distinct sum(deptno + '1') as deptsum from dept order by 1;
 +---------+
 (1 row)
 
+!ok
+
+# Test cases for [CALCITE-6437] For druid sql JSON_OBJECT() function results in RUNTIME_FAILURE when querying
+# INFORMATION_SCHEMA.COLUMNS
+select json_object('name': job, 'value': deptno) as options
+from "scott".emp
+where deptno = 10
+group by deptno, job;
++---------------------------------+
+| OPTIONS                         |
++---------------------------------+
+| {"name":"CLERK","value":10}     |
+| {"name":"MANAGER","value":10}   |
+| {"name":"PRESIDENT","value":10} |
++---------------------------------+
+(3 rows)
+
 !ok
 # End agg.iq
diff --git a/testkit/src/main/java/org/apache/calcite/test/SqlOperatorTest.java b/testkit/src/main/java/org/apache/calcite/test/SqlOperatorTest.java
index f5c978d53a42..83d57a0e77e2 100644
--- a/testkit/src/main/java/org/apache/calcite/test/SqlOperatorTest.java
+++ b/testkit/src/main/java/org/apache/calcite/test/SqlOperatorTest.java
@@ -6330,6 +6330,12 @@ void checkRegexpExtract(SqlOperatorFixture f0, FunctionAlias functionAlias) {
         "{\"foo\":{\"foo\":\"bar\"}}", "VARCHAR(2000) NOT NULL");
     f.checkString("json_object('foo': json_object('foo': 'bar') format json)",
         "{\"foo\":{\"foo\":\"bar\"}}", "VARCHAR(2000) NOT NULL");
+    final SqlOperatorFixture f1 = SqlOperatorFixtureImpl.DEFAULT.withTester(t -> TESTER);
+    f1.check(
+        "select json_object('key':x, 'value':y)\n"
+        + "from (select 1 as x, 2 as y\n"
+        + "  from (values (true)))",
+        SqlTests.ANY_TYPE_CHECKER, "{\"value\":2,\"key\":1}");
   }
 
   @Test void testJsonObjectAgg() {