diff --git a/opensearchorm/query.py b/opensearchorm/query.py
index 35e1853..741cca0 100644
--- a/opensearchorm/query.py
+++ b/opensearchorm/query.py
@@ -1,7 +1,8 @@
 import abc
+from datetime import date, datetime
 from enum import Enum
 import logging
-from typing import List, Type, TypeVar, Union
+from typing import Any, Callable, Dict, List, Tuple, Type, TypeVar, Union
 
 from opensearchorm.model import BaseModel
 
@@ -15,31 +16,45 @@ class Expr(abc.ABC):
 
 
 class Contains(Expr):
-    def __init__(self, field: str, values: list):
+    def __init__(self, field: str, values: list, min_match: int = 1):
         self.field = field
         self.values = values
+        self.min_match = min_match
 
     def compile(self):
         return {
             'bool': {
                 'should': [MatchPhrase(self.field, v).compile() for v in self.values],
-                'minimum_should_match': 1,
+                'minimum_should_match': self.min_match,
             }
         }
 
 
 class Range(Expr):
-    def __init__(self, field: str, value: Union[str, int], operator: str):
+    def __init__(self, field: str, interval: Tuple[Any, Any], *, left_open: bool = False, right_open: bool = False):
         self.field = field
-        self.op = operator
-        self.value = value
+        self.interval = interval
+        self.left_open = left_open
+        self.right_open = right_open
 
     def compile(self):
+        left, right = self.interval
+        if isinstance(left, (date, datetime)):
+            left = left.isoformat()
+        if isinstance(right, (date, datetime)):
+            right = right.isoformat()
+
+        range = {}
+        if left is not None:
+            op = 'gt' if self.left_open else 'gte'
+            range[op] = left
+        if right is not None:
+            op = 'lt' if self.right_open else 'lte'
+            range[op] = right
+
         return {
             'range': {
-                self.field: {
-                    self.op: self.value,
-                }
+                self.field: range,
             }
         }
 
@@ -57,14 +72,14 @@ class MatchPhrase(Expr):
         }
 
 
-class Prefix(Expr):
+class MatchPhrasePrefix(Expr):
     def __init__(self, field: str, value: str):
         self.field = field
         self.value = value
 
     def compile(self):
         return {
-            'prefix': {
+            'match_phrase_prefix': {
                 self.field: self.value,
             }
         }
@@ -106,6 +121,17 @@ class Operator(Enum):
     LT = '__lt'
 
 
+OPERATOR_FUNCTIONS: Dict[Operator, Callable[[str, Any], Expr]] = {
+    Operator.CONTAINS: lambda field, value: Contains(field, value),
+    Operator.PREFIX: lambda field, value: MatchPhrasePrefix(field, value),
+    Operator.REGEXP: lambda field, value: RegExp(field, value),
+    Operator.GTE: lambda field, value: Range(field, (value, None)),
+    Operator.GT: lambda field, value: Range(field, (value, None), left_open=True),
+    Operator.LTE: lambda field, value: Range(field, (None, value)),
+    Operator.LT: lambda field, value: Range(field, (None, value), right_open=True),
+}
+
+
 class ModelQuery(Expr):
     def __init__(self, model_cls: Type[Model]):
         self.__model_cls = model_cls
@@ -137,18 +163,9 @@ class ModelQuery(Expr):
             suffix: str = op.value
             if raw_field.endswith(suffix):
                 field, _ = raw_field.rsplit(suffix)
-                self.check_valid_field(field)
                 logging.debug('parse field: %s, raw: %s', field, raw_field)
-
-                if op == Operator.CONTAINS:
-                    return Contains(field, value)
-                if op == Operator.PREFIX:
-                    return Prefix(field, value)
-                if op == Operator.REGEXP:
-                    return RegExp(field, value)
-                if op in (Operator.GTE, Operator.GT, Operator.LTE, Operator.LT):
-                    op = suffix.lstrip('_')
-                    return Range(field, value, op)
+                self.check_valid_field(field)
+                return OPERATOR_FUNCTIONS[op](field, value)
 
         self.check_valid_field(field)
         return MatchPhrase(field, value)
diff --git a/opensearchorm/session.py b/opensearchorm/session.py
index a048cac..09a8126 100644
--- a/opensearchorm/session.py
+++ b/opensearchorm/session.py
@@ -6,7 +6,7 @@ from opensearchpy import OpenSearch
 
 from opensearchorm.model import BaseModel
 from opensearchorm.query import ModelQuery, Expr
-from opensearchorm.aggs import Aggregation, Sum, Cardinality
+from opensearchorm.aggs import Aggregation, Sum, Cardinality, Terms
 from opensearchorm.utils import parse_aggregations
 
 Host = Union[str, dict]
@@ -163,3 +163,6 @@ class QueryExecutor:
             **kwargs,
         )
         return resp['count']
+
+    def group_by(self, field: str, max_buckets: int = 100):
+        return self.aggregate(Terms(field, max_buckets))
diff --git a/pyproject.toml b/pyproject.toml
index 22a02bb..ff34792 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "opensearch-orm"
-version = "0.1.3"
+version = "0.1.4"
 description = ""
 authors = ["yim7 <yimchiu7@gmail.com>"]
 readme = "README.md"