php - SQL - 两个 worker 一次过滤

Question

stackoverflow 的大师们大家好。我需要 SQL 帮助。

情况:需要过滤掉 worker 并累加他们的工作时间。

数据库:

worker1    worker2    time_spent_in_seconds
X                     60
X          Y          60
Z          X          60

条件:如果worker1和worker2一起工作，他们的时间除以2 我期望得到的结果:

X=120
Y=30
Z=30

谢谢!

Answer 1

您可以使用 union all 尝试以下方式

    select worker,sum(val) from 
    (   select worker1 as worker , case when worker2 is not null
     then  time_spent/2 else time_spent end as val from test
    union all
    select worker2 , case when worker2 is not null
     then  time_spent/2 else time_spent end as val from test
    ) t where worker is not null
    group by worker

worker  sum(val)
X       120
Y       30
Z       30

Demo link