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。

This function, as mentioned in SQL standard, returns the length of the input string in octets or bytes.

youdao

除了输入字符串之外，SUBSTRING函数还有其他三个参数，它们分别是：起始位置、长度和代码单元指定。

Along with the input string, the SUBSTRING function has three other arguments, which are start position, length, and code unit specification.

youdao

您可能会感到奇怪。其实内部函数调用将输入字符串转换成使用特定格式编译的时间戳。

In case you're curious, the inner function call converts the input string into a timestamp that complies with a specific format.

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