如何在SQL中为计算表达式使用别名

Question

我有类似的东西

@CucumberOptions(features = "scenarii/connexion/", glue = { "cucumber.tests, "org.includeProject.cucumber"} )

我可以为公式CASE WHEN (1-(DayDiff([END_DATE],[START_DATE])*0.01)) >= 1.5 THEN 1.5 WHEN (1-(DayDiff([END_DATE],[START_DATE])*0.01)) <=0 THEN 0 ELSE (1-(DayDiff([END_DATE],[START_DATE])*0.01)) END使用别名吗？ 而不是多次使用它？

当公式返回(1-(DayDiff([END_DATE],[START_DATE])*0.01))时，我也希望将值设为0。

Answer 1

您可以为计算字段指定别名，并在外部查询中使用该别名。例如;

 select 
    CASE WHEN calc_field >= 1.5 THEN 1.5
    WHEN calc_field <=0 THEN 0
    ELSE calc_field 
    END result
from (
    select (1-(DayDiff([END_DATE],[START_DATE])*0.01)) calc_field
    from table
    ) K