stuff

sql/src/main/java/org/apache/druid/sql/calcite/expression/builtin/NestedDataOperatorConversions.java

@@ -722,7 +722,9 @@ public class NestedDataOperatorConversions
   public static class JsonObjectOperatorConversion implements SqlOperatorConversion
   {
     private static final String FUNCTION_NAME = "json_object";
-    private static final SqlFunction SQL_FUNCTION = OperatorConversions
+    private static final SqlFunction SQL_FUNCTION = SqlStdOperatorTable.JSON_OBJECT;
+
+    private static final SqlFunction SQL_FUNCTION0 = OperatorConversions
         .operatorBuilder(FUNCTION_NAME)
         .operandTypeChecker(OperandTypes.variadic(SqlOperandCountRanges.from(1)))
         .operandTypeInference((callBinding, returnType, operandTypes) -> {
@@ -781,7 +783,8 @@ public class NestedDataOperatorConversions
   public static class ToJsonStringOperatorConversion implements SqlOperatorConversion
   {
     private static final String FUNCTION_NAME = "to_json_string";
-    private static final SqlFunction SQL_FUNCTION = OperatorConversions
+    private static final SqlFunction SQL_FUNCTION =
+        OperatorConversions
         .operatorBuilder(StringUtils.toUpperCase(FUNCTION_NAME))
         .operandTypes(SqlTypeFamily.ANY)
         .returnTypeCascadeNullable(SqlTypeName.VARCHAR)

sql/src/test/java/org/apache/druid/sql/calcite/CalciteNestedDataQueryTest.java

@@ -4882,7 +4882,7 @@ public class CalciteNestedDataQueryTest extends BaseCalciteQueryTest
   public void testJsonQueryAndJsonObject()
   {
     testQuery(
-        "SELECT JSON_OBJECT(KEY 'n' VALUE JSON_QUERY(nester, '$.n'), KEY 'x' VALUE JSON_VALUE(nest, '$.x'))\n"
+        "SELECT TO_JSON_STRING(JSON_OBJECT(KEY 'n' VALUE JSON_QUERY(nester, '$.n'), KEY 'x' VALUE JSON_VALUE(nest, '$.x')))\n"
         + "FROM druid.nested",
         ImmutableList.of(
             Druids.newScanQueryBuilder()

sql/src/test/java/org/apache/druid/sql/calcite/CalciteSysQueryTest.java

@@ -97,4 +97,21 @@ public class CalciteSysQueryTest extends BaseCalciteQueryTest
                              + "      LogicalTableScan(table=[[sys, tasks]])\n")
         .run();
   }
+
+  @Test
+  public void testJsonObject()
+  {
+    testBuilder()
+        .sql(
+            "select JSON_OBJECT('name': COLUMN_NAME, 'type': \"DATA_TYPE\")"
+                + "from INFORMATION_SCHEMA.COLUMNS order by COLUMN_NAME limit 1"
+        )
+        .expectedResults(
+            ImmutableList.of(
+                new Object[] {"{\"name\":\"CATALOG_NAME\",\"type\":\"VARCHAR\"}"}
+            )
+        )
+        .run();
+  }
+
 }