diff --git a/FrontendWebApi/ApiControllers/HydroMeterController.cs b/FrontendWebApi/ApiControllers/HydroMeterController.cs
index 8aab0b3..902cd2d 100644
--- a/FrontendWebApi/ApiControllers/HydroMeterController.cs
+++ b/FrontendWebApi/ApiControllers/HydroMeterController.cs
@@ -1057,9 +1057,9 @@ namespace FrontendWebApi.ApiControllers
                     return Ok(apiResult);
                 }
 
-                string header_now = start_year + "_" + start_month;
-                string header_lastM = start_year + "_" + last_month;
-                string header_lastY = last_year + "_" + start_month;
+                string header_now = start_year + "-" + start_month;
+                string header_lastM = start_year + "-" + last_month;
+                string header_lastY = last_year + "-" + start_month;
 
                 var sql = $@"
 select e.full_name building_name, a.device_number, '{header_now}' searchMT, ifnull(b.kwh_sum, 0) searchM, '{header_lastM}' lastMT, ifnull(c.kwh_sum, 0) lastM, '{header_lastY}' lastYT, ifnull(d.kwh_sum, 0) lastY