Question

我有一个名为title_runtime的列，我希望以小时为单位显示几秒钟，并且还只显示运行时超过三小时的列。这就是我所拥有的，减去转换：

select title_name, title_type, title_release_year, title_runtime as title_runtime_hrs
from nf_titles
where title_release_year = '1999' or
    title_release_year = '2000' or
    title_release_year = '2001' and
    title_runtime > 3
order by title_release_year, title_runtime_hrs

Answer 1

如果除法运算中的两者均为int，则结果为int。

试试这个：

select title_name, title_type, title_release_year, title_runtime / 3600.0 as title_runtime_hrs
from nf_titles
where title_release_year = '1999' or
    title_release_year = '2000' or
    title_release_year = '2001' and
    title_runtime > 3*3600
order by title_release_year, title_runtime_hrs

Answer 2

要精确测量小时数，您需要除以3600.0。不只是3600.如果你除以3600，你将永远无法获得准确的小时数。例如，如果运行时间是1/2小时，则结果需要1.5小时。如果不除以3600.0，这是不可能的。



SELECT title_name, title_type, title_release_year, title_runtime / 3600.0 as title_runtime_hrs
FROM nf_titles
WHERE title_release_year = '1999' or
title_release_year = '2000' or
title_release_year = '2001' and
title_runtime > (3.0 * 3600.0)
order by title_release_year, title_runtime_hrs

SELECT title_name, title_type, title_release_year, title_runtime / 3600.0 as title_runtime_hrs FROM nf_titles WHERE title_release_year = '1999' or title_release_year = '2000' or title_release_year = '2001' and title_runtime > (3.0 * 3600.0) order by title_release_year, title_runtime_hrs

Answer 3

将列title_runtime除以3600。

select title_name, title_type, title_release_year, title_runtime/3600 as title_runtime_hrs
from nf_titles
where title_release_year = '1999' or
    title_release_year = '2000' or
    title_release_year = '2001' and
    title_runtime > 3*3600
order by title_release_year, title_runtime_hrs

以上查询错误，我们需要强制浮点除法，否则像1200/3600这样会将列值显示为零。

title_runtime / 3600.0 as title_runtime_hrs

显示当前以小时为单位的列？

3 个答案: