diff --git a/ibis-server/app/util.py b/ibis-server/app/util.py
index f05f61e2e..9cbed3b77 100644
--- a/ibis-server/app/util.py
+++ b/ibis-server/app/util.py
@@ -29,9 +29,18 @@ def _to_datetime_and_format(series: pd.Series) -> pd.Series:
 
 
 def _to_json_obj(df: pd.DataFrame) -> dict:
-    data = df.map(lambda x: f"{x:.9g}" if isinstance(x, float) else x).to_dict(
-        orient="split", index=False
-    )
+    def format_value(x):
+        if isinstance(x, float):
+            return f"{x:.9g}"
+        elif isinstance(x, decimal.Decimal):
+            if x == 0:
+                return "0"
+            else:
+                return x
+        else:
+            return x
+
+    data = df.map(format_value).to_dict(orient="split", index=False)
 
     def default(obj):
         if pd.isna(obj):
diff --git a/ibis-server/tests/routers/v2/connector/test_bigquery.py b/ibis-server/tests/routers/v2/connector/test_bigquery.py
index a5be020c7..764fbd5d8 100644
--- a/ibis-server/tests/routers/v2/connector/test_bigquery.py
+++ b/ibis-server/tests/routers/v2/connector/test_bigquery.py
@@ -198,6 +198,20 @@ async def test_query_values(client, manifest_str):
     assert response.status_code == 204
 
 
+async def test_scientific_notation(client, manifest_str):
+    response = await client.post(
+        url=f"{base_url}/query",
+        json={
+            "connectionInfo": connection_info,
+            "manifestStr": manifest_str,
+            "sql": "SELECT cast(0 as numeric) as col",
+        },
+    )
+    assert response.status_code == 200
+    result = response.json()
+    assert result["data"][0] == ["0"]
+
+
 async def test_query_empty_json(client, manifest_str):
     """Test the empty result with json column."""
     response = await client.post(
diff --git a/ibis-server/tests/routers/v2/connector/test_local_file.py b/ibis-server/tests/routers/v2/connector/test_local_file.py
index e882307e2..0f0b6c99c 100644
--- a/ibis-server/tests/routers/v2/connector/test_local_file.py
+++ b/ibis-server/tests/routers/v2/connector/test_local_file.py
@@ -331,7 +331,7 @@ async def test_list_csv_files(client):
     assert "type-test" in table_names
     # `invalid` will be considered as a one column csv file
     assert "invalid" in table_names
-    columns = result[0]["columns"]
+    columns = next(filter(lambda x: x["name"] == "type-test-csv", result))["columns"]
     assert columns[0]["name"] == "c_bigint"
     assert columns[0]["type"] == "INT64"
     assert columns[1]["name"] == "c_bit"