我试图使用mysql实现黑客新闻算法并得到以下错误
Double value is out of range in
pow(((unix_timestamp() - unix_timestamp(postDateTime))/3600 + 1),1.5)
Where the value of postDateTime is 2012-12-15 10:41:31
如果我将上述实现为
pow(((unix_timestamp() - unix_timestamp(cast(postDateTime as signed)))/3600 + 1),1.5)
它工作完美，但我不明白其背后的原因
最佳答案
您运行的 mysql 版本是什么？检查this link出来。
并检查the documentation了解为什么您会得到负值:
If called with no argument, returns a Unix timestamp (seconds since '1970-01-01 00:00:00' UTC) as an unsigned integer. If UNIX_TIMESTAMP() is called with a date argument, it returns the value of the argument as seconds since '1970-01-01 00:00:00' UTC. date may be a DATE string, a DATETIME string, a TIMESTAMP, or a number in the format YYMMDD or YYYYMMDD. The server interprets date as a value in the current time zone and converts it to an internal value in UTC.
...
If you want to subtract UNIX_TIMESTAMP() columns, you might want to cast the result to signed integers. See Section 12.10, “Cast Functions and Operators”.
关于mysql - mysql 出现超出范围错误，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/13891809/