This function, as mentioned in SQL standard, returns the length of the input string in octets or bytes.
如 SQL 标准中所述，此函数返回输入字符串的八位字节长度或字节长度。
2
An input device, sometimes part of a standard typewriter keyboard, consisting of a separate grid of numerical and function keys arranged for efficient data entry.
一种输入设备，有时是指标准打字机键盘的一部分，包括一个单独的用于有效数据输入的数字和功能键网格。
3
This function is typically used to open a specified file as one of the predefined streams: standardinput, standard output, or standard error.