diff --git a/lib/adapters/mysql.js b/lib/adapters/mysql.js
index 3b0ad279..74acca95 100644
--- a/lib/adapters/mysql.js
+++ b/lib/adapters/mysql.js
@@ -241,6 +241,9 @@ MySQL.prototype.all = function all(model, filter, callback) {
                 cs.push(keyEscaped + ' = ' + val);
             }
         });
+        if (cs.length === 0) {
+          return '';
+        }
         return 'WHERE ' + cs.join(' AND ');
     }