diff --git a/mylib/db.py b/mylib/db.py
index d0dc3c7..efc8001 100644
--- a/mylib/db.py
+++ b/mylib/db.py
@@ -192,6 +192,17 @@ class DB:
             params[param] = value
         return params
 
+    @staticmethod
+    def _get_unique_param_name(field, params):
+        """Return a unique parameter name based on specified field name"""
+        param = field
+        if field in params:
+            idx = 1
+            while param in params:
+                param = f"{field}_{idx}"
+                idx += 1
+        return param
+
     @classmethod
     def _format_where_clauses(cls, where_clauses, params=None, where_op=None):
         """
@@ -237,16 +248,22 @@ class DB:
         if isinstance(where_clauses, dict):
             sql_where_clauses = []
             for field, value in where_clauses.items():
-                param = field
-                if field in params:
-                    idx = 1
-                    while param in params:
-                        param = f"{field}_{idx}"
-                        idx += 1
-                cls._combine_params(params, {param: value})
-                sql_where_clauses.append(
-                    f"{cls._quote_field_name(field)} = {cls.format_param(param)}"
-                )
+                if isinstance(value, list):
+                    param_names = []
+                    for idx, v in enumerate(value):
+                        param = cls._get_unique_param_name(f"{field}_{idx}", params)
+                        cls._combine_params(params, **{param: v})
+                        param_names.append(param)
+                    sql_where_clauses.append(
+                        f"{cls._quote_field_name(field)} IN "
+                        f"({', '.join([cls.format_param(param) for param in param_names])})"
+                    )
+                else:
+                    param = cls._get_unique_param_name(field, params)
+                    cls._combine_params(params, **{param: value})
+                    sql_where_clauses.append(
+                        f"{cls._quote_field_name(field)} = {cls.format_param(param)}"
+                    )
             return (f" {where_op} ".join(sql_where_clauses), params)
         raise DBUnsupportedWHEREClauses(where_clauses)