diff --git a/lib/worker.js b/lib/worker.js
index 2ea5e05..a508e77 100644
--- a/lib/worker.js
+++ b/lib/worker.js
@@ -292,11 +292,11 @@ function updatePoolStats(poolType) {
         function (callback) {
             debug(threadName + "Checking MySQL for total miners paid");
             if (typeof(poolType) !== 'undefined') {
-                global.mysql.query("SELECT id FROM payments WHERE pool_type = ? group by payment_address, payment_id, id", [poolType]).then(function (rows) {
+                global.mysql.query("SELECT payment_address, payment_id FROM payments WHERE pool_type = ? group by payment_address, payment_id", [poolType]).then(function (rows) {
                     return callback(null, rows.length);
                 });
             } else {
-                global.mysql.query("SELECT id FROM payments group by payment_address, payment_id, id").then(function (rows) {
+                global.mysql.query("SELECT payment_address, payment_id FROM payments group by payment_address, payment_id").then(function (rows) {
                     return callback(null, rows.length);
                 });
             }