Question

描述

选择最大反射率值作为最大和最小反射率值为min where 波长在650和800之间，并应用公式（max + min）/ 2 + min作为辐亮度
选择波长接近700的反射率为r700和
选择波长接近740的反射率为r740

应用公式

700+（辐射-R700）/（R740-R700）* 40

输出值为radtera，我想显示辐射值和radtera值作为输出

我尝试了这个查询，它在辐射中显示了很多值，它在radtera中显示了许多空值，但我只想显示一个辐亮度值和一个radtera值

SELECT radiance, (700+(radiance-r700))/((r740-r700)*40) as radtera
FROM (
  SELECT (MAX(reflectance)+MIN(reflectance))/2+MIN(reflectance) as radiance, 
         case when wavelength=700 then reflectance end as r700,
         case when wavelength=740 then reflectance end as r740
  FROM table_name
  WHERE wavelength between 650 and 800
  GROUP BY wavelength,reflectance
) AS SE_23693370

如果我删除

GROUP BY波长，反射率

这来自查询，它显示错误

这是SQL fiddle。

我检查了一下，我不知道它是如何显示许多值而不是一个值显示..任何人帮我纠正错误请...

我尝试在SQL fiddle中使用案例陈述。

select reip,700+(reip-r45)/(r72-r45)*40 as reipw
from ( 
  select (mx+mn))/2+mn as reip 
from ( 
  select case max(tert) as mx, 
  case min(tert) as mn 
  case when iner=44.5 then tert end as r45, 
  case when iner=72.1 then tert end as r72
  from  table_name
  where iner between 43 and 79)bar
)as SE_23693370

它显示*错误：FROM中的子查询必须有一个别名：select select，700 +（reip-r45）/（r72-r45） 40作为从（select（mx + mn））/ 2+的重入mn作为reip from（选择case max（tert）作为mx，case min（tert）作为mn情况，当iner = 44.5然后tert结束为r45，情况当iner = 72.1然后tert结束作为r72来自table_name，其中iner在43和79之间））作为SE_23693370

Answer 1

您可以使用ROW_NUMBER功能执行此操作。它可以在SQL Server，Oracle和PostgreSQL等处使用。

select radiance, r700, r740,
  (700+(radiance-r700))/((r740-r700)*40) as radtera
from
(select t.reflectance as radiance, 
  t700.wavelength as r700, t740.wavelength as r740
from
  (select max(reflectance) as reflectance
  from table_name) t,
    (SELECT reflectance, wavelength,
      row_number() over (order by abs(wavelength-700)) as rn700
    FROM table_name
    WHERE wavelength between 650 and 800) as t700,
   (SELECT reflectance,wavelength,
      row_number() over (order by abs(wavelength-740)) as rn740
    FROM table_name
    WHERE wavelength between 650 and 800) as t740
  where t700.rn700=1 and t740.rn740=1) as di

Fiddle

一个Query输出在另一个查询中执行

1 个答案: