This function returns the number of affected rows on success, or -1 if the last operation failed.
This function returns the number of affected rows on success, or -1 if the last operation failed.
如果该函数成功执行，将返回记录行数；如果失败，将返回“-1”。
This function returns the number of affected rows on success, or -1 if the last operation failed.
如果该函数成功执行，将返回记录行数；如果失败，将返回“-1”。