!6 修复查询bigint时自动转为科学计数的BUG

Merge pull request !6 from 天宇/master

library/think/db/Connection.php

@@ -483,7 +483,7 @@ abstract class Connection
             if (PDO::PARAM_STR == $type) {
                 $value = $this->quote($value);
             } elseif (PDO::PARAM_INT == $type) {
-                $value = (float) $value;
+                $value = sprintf("%d", $value);
             }
             // 判断占位符
             $sql = is_numeric($key) ?