获得最后一个执行的错误.
$database->select("bccount", [ "user_name", "email"], [ "user_id[ 20]);var_dump($database->error());// array(3) { [0]=> string(5) "42S02" [1]=> int(1146) [2]=> string(36) "Table 'my_database.bccount' doesn't exist" }
