diff --git a/lib/dml/mssql_native_moodle_database.php b/lib/dml/mssql_native_moodle_database.php
index f9e980b7f2b..ecdf3bd92d4 100644
--- a/lib/dml/mssql_native_moodle_database.php
+++ b/lib/dml/mssql_native_moodle_database.php
@@ -1218,7 +1218,7 @@ class mssql_native_moodle_database extends moodle_database {
     }
 
     public function sql_order_by_text($fieldname, $numchars=32) {
-        return ' CONVERT(varchar, ' . $fieldname . ', ' . $numchars . ')';
+        return " CONVERT(varchar({$numchars}), {$fieldname})";
     }
 
    /**
diff --git a/lib/dml/sqlsrv_native_moodle_database.php b/lib/dml/sqlsrv_native_moodle_database.php
index 20cd8a1e14e..8352d76f2cb 100644
--- a/lib/dml/sqlsrv_native_moodle_database.php
+++ b/lib/dml/sqlsrv_native_moodle_database.php
@@ -1281,7 +1281,7 @@ class sqlsrv_native_moodle_database extends moodle_database {
     }
 
     public function sql_order_by_text($fieldname, $numchars = 32) {
-        return ' CONVERT(varchar, '.$fieldname.', '.$numchars.')';
+        return " CONVERT(varchar({$numchars}), {$fieldname})";
     }
 
     /**