diff --git a/redash/query_runner/query_results.py b/redash/query_runner/query_results.py
index ea83e5089b..b22bac556f 100644
--- a/redash/query_runner/query_results.py
+++ b/redash/query_runner/query_results.py
@@ -1,3 +1,4 @@
+import decimal
 import hashlib
 import logging
 import re
@@ -105,6 +106,8 @@ def fix_column_name(name):
 def flatten(value):
     if isinstance(value, (list, dict)):
         return json_dumps(value)
+    elif isinstance(value, decimal.Decimal):
+        return float(value)
     else:
         return value
 
diff --git a/tests/query_runner/test_query_results.py b/tests/query_runner/test_query_results.py
index d9eb45ae42..756797492c 100644
--- a/tests/query_runner/test_query_results.py
+++ b/tests/query_runner/test_query_results.py
@@ -1,3 +1,4 @@
+import decimal
 import sqlite3
 from unittest import TestCase
 
@@ -107,6 +108,16 @@ def test_creates_table_with_non_ascii_in_column_name(self):
         create_table(connection, table_name, results)
         connection.execute("SELECT 1 FROM query_123")
 
+    def test_creates_table_with_decimal_in_column_value(self):
+        connection = sqlite3.connect(":memory:")
+        results = {
+            "columns": [{"name": "test1"}, {"name": "test2"}],
+            "rows": [{"test1": 1, "test2": decimal.Decimal(2)}],
+        }
+        table_name = "query_123"
+        create_table(connection, table_name, results)
+        connection.execute("SELECT 1 FROM query_123")
+
     def test_shows_meaningful_error_on_failure_to_create_table(self):
         connection = sqlite3.connect(":memory:")
         results = {"columns": [], "rows": []}