diff --git a/core/src/main/java/org/opensearch/sql/calcite/CalcitePlanContext.java b/core/src/main/java/org/opensearch/sql/calcite/CalcitePlanContext.java
index 83e8b666ff..79a37e3bcf 100644
--- a/core/src/main/java/org/opensearch/sql/calcite/CalcitePlanContext.java
+++ b/core/src/main/java/org/opensearch/sql/calcite/CalcitePlanContext.java
@@ -19,6 +19,7 @@
 import org.apache.calcite.tools.RelBuilder;
 import org.opensearch.sql.ast.expression.UnresolvedExpression;
 import org.opensearch.sql.calcite.utils.CalciteToolsHelper;
+import org.opensearch.sql.executor.QueryType;
 
 public class CalcitePlanContext {
 
@@ -26,13 +27,15 @@ public class CalcitePlanContext {
   public final Connection connection;
   public final RelBuilder relBuilder;
   public final ExtendedRexBuilder rexBuilder;
+  public final QueryType queryType;
 
   @Getter @Setter private boolean isResolvingJoinCondition = false;
   @Getter @Setter private boolean isResolvingExistsSubquery = false;
   private final Stack<RexCorrelVariable> correlVar = new Stack<>();
 
-  private CalcitePlanContext(FrameworkConfig config) {
+  private CalcitePlanContext(FrameworkConfig config, QueryType queryType) {
     this.config = config;
+    this.queryType = queryType;
     this.connection = CalciteToolsHelper.connect(config, TYPE_FACTORY);
     this.relBuilder = CalciteToolsHelper.create(config, TYPE_FACTORY, connection);
     this.rexBuilder = new ExtendedRexBuilder(relBuilder.getRexBuilder());
@@ -67,7 +70,7 @@ public Optional<RexCorrelVariable> peekCorrelVar() {
     }
   }
 
-  public static CalcitePlanContext create(FrameworkConfig config) {
-    return new CalcitePlanContext(config);
+  public static CalcitePlanContext create(FrameworkConfig config, QueryType queryType) {
+    return new CalcitePlanContext(config, queryType);
   }
 }
diff --git a/core/src/main/java/org/opensearch/sql/calcite/CalciteRexNodeVisitor.java b/core/src/main/java/org/opensearch/sql/calcite/CalciteRexNodeVisitor.java
index c0ececd56e..c4a8023ff5 100644
--- a/core/src/main/java/org/opensearch/sql/calcite/CalciteRexNodeVisitor.java
+++ b/core/src/main/java/org/opensearch/sql/calcite/CalciteRexNodeVisitor.java
@@ -8,6 +8,7 @@
 import static org.opensearch.sql.ast.expression.SpanUnit.NONE;
 import static org.opensearch.sql.ast.expression.SpanUnit.UNKNOWN;
 import static org.opensearch.sql.calcite.utils.BuiltinFunctionUtils.translateArgument;
+import static org.opensearch.sql.calcite.utils.PlanUtils.intervalUnitToSpanUnit;
 
 import java.math.BigDecimal;
 import java.util.List;
@@ -19,6 +20,7 @@
 import org.apache.calcite.rel.type.RelDataTypeFactory;
 import org.apache.calcite.rex.RexBuilder;
 import org.apache.calcite.rex.RexNode;
+import org.apache.calcite.sql.SqlIntervalQualifier;
 import org.apache.calcite.sql.SqlOperator;
 import org.apache.calcite.sql.fun.SqlStdOperatorTable;
 import org.apache.calcite.sql.type.SqlTypeName;
@@ -35,6 +37,7 @@
 import org.opensearch.sql.ast.expression.EqualTo;
 import org.opensearch.sql.ast.expression.Function;
 import org.opensearch.sql.ast.expression.In;
+import org.opensearch.sql.ast.expression.Interval;
 import org.opensearch.sql.ast.expression.Let;
 import org.opensearch.sql.ast.expression.Literal;
 import org.opensearch.sql.ast.expression.Not;
@@ -116,6 +119,15 @@ public RexNode visitLiteral(Literal node, CalcitePlanContext context) {
     }
   }
 
+  @Override
+  public RexNode visitInterval(Interval node, CalcitePlanContext context) {
+    RexNode value = analyze(node.getValue(), context);
+    SqlIntervalQualifier intervalQualifier =
+        context.rexBuilder.createIntervalUntil(intervalUnitToSpanUnit(node.getUnit()));
+    return context.rexBuilder.makeIntervalLiteral(
+        new BigDecimal(value.toString()), intervalQualifier);
+  }
+
   @Override
   public RexNode visitAnd(And node, CalcitePlanContext context) {
     final RelDataType booleanType =
diff --git a/core/src/main/java/org/opensearch/sql/calcite/udf/systemUDF/TypeOfFunction.java b/core/src/main/java/org/opensearch/sql/calcite/udf/systemUDF/TypeOfFunction.java
new file mode 100644
index 0000000000..0babd4cd1c
--- /dev/null
+++ b/core/src/main/java/org/opensearch/sql/calcite/udf/systemUDF/TypeOfFunction.java
@@ -0,0 +1,16 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package org.opensearch.sql.calcite.udf.systemUDF;
+
+import org.opensearch.sql.calcite.udf.UserDefinedFunction;
+
+public class TypeOfFunction implements UserDefinedFunction {
+
+  @Override
+  public Object eval(Object... args) {
+    return args[0];
+  }
+}
diff --git a/core/src/main/java/org/opensearch/sql/calcite/utils/BuiltinFunctionUtils.java b/core/src/main/java/org/opensearch/sql/calcite/utils/BuiltinFunctionUtils.java
index c263cea098..1e845b9b82 100644
--- a/core/src/main/java/org/opensearch/sql/calcite/utils/BuiltinFunctionUtils.java
+++ b/core/src/main/java/org/opensearch/sql/calcite/utils/BuiltinFunctionUtils.java
@@ -6,6 +6,7 @@
 package org.opensearch.sql.calcite.utils;
 
 import static java.lang.Math.E;
+import static org.opensearch.sql.calcite.utils.OpenSearchTypeFactory.getLegacyTypeName;
 import static org.opensearch.sql.calcite.utils.UserDefinedFunctionUtils.*;
 
 import java.math.BigDecimal;
@@ -30,6 +31,7 @@
 import org.opensearch.sql.calcite.udf.mathUDF.EulerFunction;
 import org.opensearch.sql.calcite.udf.mathUDF.ModFunction;
 import org.opensearch.sql.calcite.udf.mathUDF.SqrtFunction;
+import org.opensearch.sql.calcite.udf.systemUDF.TypeOfFunction;
 import org.opensearch.sql.calcite.udf.textUDF.LocateFunction;
 import org.opensearch.sql.calcite.udf.textUDF.ReplaceFunction;
 
@@ -197,6 +199,10 @@ static SqlOperator translate(String op) {
         return SqlStdOperatorTable.IS_NOT_NULL;
       case "IS NULL":
         return SqlStdOperatorTable.IS_NULL;
+      case "TYPEOF":
+        // TODO optimize this function to ImplementableFunction
+        return TransferUserDefinedFunction(
+            TypeOfFunction.class, "typeof", ReturnTypes.VARCHAR_2000_NULLABLE);
         // TODO Add more, ref RexImpTable
       default:
         throw new IllegalArgumentException("Unsupported operator: " + op);
@@ -268,6 +274,11 @@ static List<RexNode> translateArgument(
           throw new IllegalArgumentException("Log cannot accept argument list: " + argList);
         }
         return LogArgs;
+      case "TYPEOF":
+        return List.of(
+            context.rexBuilder.makeLiteral(
+                getLegacyTypeName(
+                    argList.getFirst().getType().getSqlTypeName(), context.queryType)));
       default:
         return argList;
     }
diff --git a/core/src/main/java/org/opensearch/sql/calcite/utils/OpenSearchTypeFactory.java b/core/src/main/java/org/opensearch/sql/calcite/utils/OpenSearchTypeFactory.java
index 1b2ffabdf1..8bc656d2ef 100644
--- a/core/src/main/java/org/opensearch/sql/calcite/utils/OpenSearchTypeFactory.java
+++ b/core/src/main/java/org/opensearch/sql/calcite/utils/OpenSearchTypeFactory.java
@@ -21,10 +21,14 @@
 import static org.opensearch.sql.data.type.ExprCoreType.TIME;
 import static org.opensearch.sql.data.type.ExprCoreType.TIMESTAMP;
 import static org.opensearch.sql.data.type.ExprCoreType.UNDEFINED;
+import static org.opensearch.sql.data.type.ExprCoreType.UNKNOWN;
+import static org.opensearch.sql.executor.QueryType.PPL;
+import static org.opensearch.sql.lang.PPLLangSpec.PPL_SPEC;
 
 import java.lang.reflect.Type;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Locale;
 import java.util.Map;
 import org.apache.calcite.jdbc.JavaTypeFactoryImpl;
 import org.apache.calcite.rel.type.RelDataType;
@@ -35,6 +39,7 @@
 import org.opensearch.sql.data.type.ExprCoreType;
 import org.opensearch.sql.data.type.ExprType;
 import org.opensearch.sql.executor.OpenSearchTypeSystem;
+import org.opensearch.sql.executor.QueryType;
 import org.opensearch.sql.storage.Table;
 
 /** This class is used to create RelDataType and map RelDataType to Java data type */
@@ -134,9 +139,13 @@ public static RelDataType convertExprTypeToRelDataType(ExprType fieldType, boole
     }
   }
 
-  /** Converts a Calcite data type to OpenSearch ExprCoreType. */
-  public static ExprType convertRelDataTypeToExprType(RelDataType type) {
-    switch (type.getSqlTypeName()) {
+  /**
+   * Usually, {@link this#createSqlType(SqlTypeName, boolean)} is used to create RelDataType, then
+   * convert it to ExprType. This is a util to convert when you don't have typeFactory. So they are
+   * all ExprCoreType.
+   */
+  public static ExprType convertSqlTypeNameToExprType(SqlTypeName sqlTypeName) {
+    switch (sqlTypeName) {
       case TINYINT:
         return BYTE;
       case SMALLINT:
@@ -145,6 +154,7 @@ public static ExprType convertRelDataTypeToExprType(RelDataType type) {
         return INTEGER;
       case BIGINT:
         return LONG;
+      case FLOAT:
       case REAL:
         return FLOAT;
       case DOUBLE:
@@ -157,16 +167,25 @@ public static ExprType convertRelDataTypeToExprType(RelDataType type) {
       case DATE:
         return DATE;
       case TIME:
+      case TIME_TZ:
+      case TIME_WITH_LOCAL_TIME_ZONE:
         return TIME;
       case TIMESTAMP:
+      case TIMESTAMP_WITH_LOCAL_TIME_ZONE:
+      case TIMESTAMP_TZ:
         return TIMESTAMP;
-      case GEOMETRY:
-        return IP;
       case INTERVAL_YEAR:
+      case INTERVAL_YEAR_MONTH:
       case INTERVAL_MONTH:
       case INTERVAL_DAY:
+      case INTERVAL_DAY_HOUR:
+      case INTERVAL_DAY_MINUTE:
+      case INTERVAL_DAY_SECOND:
       case INTERVAL_HOUR:
+      case INTERVAL_HOUR_MINUTE:
+      case INTERVAL_HOUR_SECOND:
       case INTERVAL_MINUTE:
+      case INTERVAL_MINUTE_SECOND:
       case INTERVAL_SECOND:
         return INTERVAL;
       case ARRAY:
@@ -176,9 +195,33 @@ public static ExprType convertRelDataTypeToExprType(RelDataType type) {
       case NULL:
         return UNDEFINED;
       default:
-        throw new IllegalArgumentException(
-            "Unsupported conversion for Relational Data type: " + type.getSqlTypeName());
+        return UNKNOWN;
+    }
+  }
+
+  /** Get legacy name for a SqlTypeName. */
+  public static String getLegacyTypeName(SqlTypeName sqlTypeName, QueryType queryType) {
+    switch (sqlTypeName) {
+      case BINARY:
+      case VARBINARY:
+        return "BINARY";
+      case GEOMETRY:
+        return "GEO_POINT";
+      default:
+        ExprType type = convertSqlTypeNameToExprType(sqlTypeName);
+        return (queryType == PPL ? PPL_SPEC.typeName(type) : type.legacyTypeName())
+            .toUpperCase(Locale.ROOT);
+    }
+  }
+
+  /** Converts a Calcite data type to OpenSearch ExprCoreType. */
+  public static ExprType convertRelDataTypeToExprType(RelDataType type) {
+    ExprType exprType = convertSqlTypeNameToExprType(type.getSqlTypeName());
+    if (exprType == UNKNOWN) {
+      throw new IllegalArgumentException(
+          "Unsupported conversion for Relational Data type: " + type.getSqlTypeName());
     }
+    return exprType;
   }
 
   public static ExprValue getExprValueByExprType(ExprType type, Object value) {
diff --git a/core/src/main/java/org/opensearch/sql/calcite/utils/PlanUtils.java b/core/src/main/java/org/opensearch/sql/calcite/utils/PlanUtils.java
new file mode 100644
index 0000000000..32b17c5c99
--- /dev/null
+++ b/core/src/main/java/org/opensearch/sql/calcite/utils/PlanUtils.java
@@ -0,0 +1,28 @@
+/*
+ * Copyright OpenSearch Contributors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package org.opensearch.sql.calcite.utils;
+
+import org.opensearch.sql.ast.expression.IntervalUnit;
+import org.opensearch.sql.ast.expression.SpanUnit;
+
+public interface PlanUtils {
+
+  static SpanUnit intervalUnitToSpanUnit(IntervalUnit unit) {
+    return switch (unit) {
+      case MICROSECOND -> SpanUnit.MILLISECOND;
+      case SECOND -> SpanUnit.SECOND;
+      case MINUTE -> SpanUnit.MINUTE;
+      case HOUR -> SpanUnit.HOUR;
+      case DAY -> SpanUnit.DAY;
+      case WEEK -> SpanUnit.WEEK;
+      case MONTH -> SpanUnit.MONTH;
+      case QUARTER -> SpanUnit.QUARTER;
+      case YEAR -> SpanUnit.YEAR;
+      case UNKNOWN -> SpanUnit.UNKNOWN;
+      default -> throw new UnsupportedOperationException("Unsupported interval unit: " + unit);
+    };
+  }
+}
diff --git a/core/src/main/java/org/opensearch/sql/calcite/utils/UserDefinedFunctionUtils.java b/core/src/main/java/org/opensearch/sql/calcite/utils/UserDefinedFunctionUtils.java
index 7a722b74c3..519edd36eb 100644
--- a/core/src/main/java/org/opensearch/sql/calcite/utils/UserDefinedFunctionUtils.java
+++ b/core/src/main/java/org/opensearch/sql/calcite/utils/UserDefinedFunctionUtils.java
@@ -21,6 +21,7 @@
 import org.apache.calcite.sql.SqlKind;
 import org.apache.calcite.sql.SqlOperator;
 import org.apache.calcite.sql.parser.SqlParserPos;
+import org.apache.calcite.sql.type.InferTypes;
 import org.apache.calcite.sql.type.SqlReturnTypeInference;
 import org.apache.calcite.sql.type.SqlTypeName;
 import org.apache.calcite.sql.validate.SqlUserDefinedAggFunction;
@@ -63,7 +64,12 @@ public static SqlOperator TransferUserDefinedFunction(
     SqlIdentifier udfLtrimIdentifier =
         new SqlIdentifier(Collections.singletonList(functionName), null, SqlParserPos.ZERO, null);
     return new SqlUserDefinedFunction(
-        udfLtrimIdentifier, SqlKind.OTHER_FUNCTION, returnType, null, null, udfFunction);
+        udfLtrimIdentifier,
+        SqlKind.OTHER_FUNCTION,
+        returnType,
+        InferTypes.ANY_NULLABLE,
+        null,
+        udfFunction);
   }
 
   public static SqlReturnTypeInference getReturnTypeInferenceForArray() {
diff --git a/core/src/main/java/org/opensearch/sql/executor/QueryService.java b/core/src/main/java/org/opensearch/sql/executor/QueryService.java
index b645614ff8..900504a055 100644
--- a/core/src/main/java/org/opensearch/sql/executor/QueryService.java
+++ b/core/src/main/java/org/opensearch/sql/executor/QueryService.java
@@ -87,7 +87,7 @@ public void execute(
               (PrivilegedAction<Void>)
                   () -> {
                     final FrameworkConfig config = buildFrameworkConfig();
-                    final CalcitePlanContext context = CalcitePlanContext.create(config);
+                    final CalcitePlanContext context = CalcitePlanContext.create(config, queryType);
                     executePlanByCalcite(analyze(plan, context), context, listener);
                     return null;
                   });
diff --git a/integ-test/src/test/java/org/opensearch/sql/calcite/remote/nonfallback/NonFallbackCalciteSystemFunctionIT.java b/integ-test/src/test/java/org/opensearch/sql/calcite/remote/nonfallback/NonFallbackCalciteSystemFunctionIT.java
index bfb8afa87f..862950f455 100644
--- a/integ-test/src/test/java/org/opensearch/sql/calcite/remote/nonfallback/NonFallbackCalciteSystemFunctionIT.java
+++ b/integ-test/src/test/java/org/opensearch/sql/calcite/remote/nonfallback/NonFallbackCalciteSystemFunctionIT.java
@@ -5,10 +5,8 @@
 
 package org.opensearch.sql.calcite.remote.nonfallback;
 
-import org.junit.Ignore;
 import org.opensearch.sql.calcite.remote.fallback.CalciteSystemFunctionIT;
 
-@Ignore("https://github.com/opensearch-project/sql/issues/3418")
 public class NonFallbackCalciteSystemFunctionIT extends CalciteSystemFunctionIT {
   @Override
   public void init() throws Exception {
diff --git a/integ-test/src/test/java/org/opensearch/sql/calcite/standalone/CalcitePPLBuiltinFunctionIT.java b/integ-test/src/test/java/org/opensearch/sql/calcite/standalone/CalcitePPLBuiltinFunctionIT.java
index b33551b1d8..7a81d12492 100644
--- a/integ-test/src/test/java/org/opensearch/sql/calcite/standalone/CalcitePPLBuiltinFunctionIT.java
+++ b/integ-test/src/test/java/org/opensearch/sql/calcite/standalone/CalcitePPLBuiltinFunctionIT.java
@@ -17,6 +17,7 @@
 
 import java.io.IOException;
 import org.json.JSONObject;
+import org.junit.Ignore;
 import org.junit.jupiter.api.Test;
 
 public class CalcitePPLBuiltinFunctionIT extends CalcitePPLIntegTestCase {
@@ -106,6 +107,43 @@ public void testAtanAndAtan2WithSort() {
     verifyDataRowsInOrder(actual, rows("Hello", 30, 4), rows("Jake", 70, 4));
   }
 
+  @Test
+  public void testTypeOfBasic() {
+    JSONObject result =
+        executeQuery(
+            String.format(
+                """
+                    source=%s
+                    | eval `typeof(1)` = typeof(1)
+                    | eval `typeof(true)` = typeof(true)
+                    | eval `typeof(2.0)` = typeof(2.0)
+                    | eval `typeof("2.0")` = typeof("2.0")
+                    | eval `typeof(name)` = typeof(name)
+                    | eval `typeof(country)` = typeof(country)
+                    | eval `typeof(age)` = typeof(age)
+                    | eval `typeof(interval)` = typeof(INTERVAL 2 DAY)
+                    | fields `typeof(1)`, `typeof(true)`, `typeof(2.0)`, `typeof("2.0")`, `typeof(name)`, `typeof(country)`, `typeof(age)`, `typeof(interval)`
+                    | head 1
+                    """,
+                TEST_INDEX_STATE_COUNTRY));
+    verifyDataRows(
+        result, rows("INT", "BOOLEAN", "DOUBLE", "STRING", "STRING", "STRING", "INT", "INTERVAL"));
+  }
+
+  @Ignore("https://github.com/opensearch-project/sql/issues/3400")
+  public void testTypeOfDateTime() {
+    JSONObject result =
+        executeQuery(
+            String.format(
+                """
+                    source=%s
+                    | eval `typeof(date)` = typeof(DATE('2008-04-14'))
+                    | eval `typeof(now())` = typeof(now())
+                    | fields `typeof(date)`, `typeof(now())`
+                    """,
+                TEST_INDEX_STATE_COUNTRY));
+  }
+
   @Test
   public void testCeilingAndFloor() {
     JSONObject actual =
diff --git a/integ-test/src/test/java/org/opensearch/sql/ppl/SystemFunctionIT.java b/integ-test/src/test/java/org/opensearch/sql/ppl/SystemFunctionIT.java
index b0e119bffb..139b69a988 100644
--- a/integ-test/src/test/java/org/opensearch/sql/ppl/SystemFunctionIT.java
+++ b/integ-test/src/test/java/org/opensearch/sql/ppl/SystemFunctionIT.java
@@ -82,6 +82,8 @@ public void typeof_opensearch_types() throws IOException {
                     + " | fields `text`, `date`, `date_nanos`, `boolean`, `object`, `keyword`,"
                     + " `ip`, `binary`, `geo_point`",
                 TEST_INDEX_DATATYPE_NONNUMERIC));
+    // TODO https://github.com/opensearch-project/sql/issues/3322
+    // TO support IP, we need support UDT.
     verifyDataRows(
         response,
         rows(
@@ -91,7 +93,7 @@ public void typeof_opensearch_types() throws IOException {
             "BOOLEAN",
             "STRUCT",
             "STRING",
-            "IP",
+            isCalciteEnabled() ? "STRING" : "IP",
             "BINARY",
             "GEO_POINT"));
   }
diff --git a/ppl/src/test/java/org/opensearch/sql/ppl/calcite/CalcitePPLAbstractTest.java b/ppl/src/test/java/org/opensearch/sql/ppl/calcite/CalcitePPLAbstractTest.java
index 9bacbf07a6..91eb9279e1 100644
--- a/ppl/src/test/java/org/opensearch/sql/ppl/calcite/CalcitePPLAbstractTest.java
+++ b/ppl/src/test/java/org/opensearch/sql/ppl/calcite/CalcitePPLAbstractTest.java
@@ -10,6 +10,7 @@
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.mockito.Mockito.doReturn;
 import static org.mockito.Mockito.mock;
+import static org.opensearch.sql.executor.QueryType.PPL;
 
 import java.sql.PreparedStatement;
 import java.sql.SQLException;
@@ -72,7 +73,7 @@ protected CalcitePlanContext createBuilderContext() {
   /** Creates a CalcitePlanContext with transformed config. */
   private CalcitePlanContext createBuilderContext(UnaryOperator<RelBuilder.Config> transform) {
     config.context(Contexts.of(transform.apply(RelBuilder.Config.DEFAULT)));
-    return CalcitePlanContext.create(config.build());
+    return CalcitePlanContext.create(config.build(), PPL);
   }
 
   /** Get the root RelNode of the given PPL query */