是否有可能在組中使用大於等於運算符？

Question

請建議我在sql中使用大於等於運算符的方式。

不管你想要做

Answer 1

，這是我能想到的唯一的事情：

... 
GROUP BY 
    CASE WHEN A >= 1 THEN 1 
    ELSE 0 
    END 

Answer 2

如果你在談論使用>運算符和GROUP BY子句，則：

select 
case when age between 0 and 20 then '0 - 20' 
    when age between 21 and 40 then '21 - 40' 
else '> 40' end age, 
sum(case when survived = 1 then else 0 end) survivors 
from rms_titanic 
group by 
case when age between 0 and 20 then '0 - 20' 
    when age between 21 and 40 then '21 - 40' 
else '> 40' 
order by 
case when age between 0 and 20 then '0 - 20' 
    when age between 21 and 40 then '21 - 40' 
else '> 40'; 

這可以寫成：

select 
case when age between 0 and 20 then '0 - 20' 
    when age between 21 and 40 then '21 - 40' 
else '> 40' end age, 
sum(case when survived = 1 then else 0 end) survivors 
from rms_titanic 
group by 1 
order by 1; 

但是，如果你想使用>對結果集的GROUP BY的運營商，T你將不得不包括HAVING子句：

select 
case when age between 0 and 20 then '0 - 20' 
    when age between 21 and 40 then '21 - 40' 
else '> 40' end age, 
passenger_class, 
sum(case when survived = 1 then else 0 end) survivors 
from rms_titanic 
group by 1, passenger_class having count(*) > 20 
order by 1;