如何用三种不同的条件对同一列进行三次查询？

Question

在 SQL-语句中，我需要使用三种不同的条件对同一列进行三次查询。我需要为所有位置显示 CC.HR1*WLL17.Hours 的总和，但具有三种不同的条件。我在 SELECT 语句中尝试了一个子查询，但是我只得到了总和，而不是按位置分组的总和。

SELECT WLL17.Location, (SELECT SUM(CC.HR1*WLL17.Hours) FROM WLL17 INNER JOIN CC ON WLL17.CC=CC.CC WHERE WLL17.EE = "Post Gate 60 (PV)") AS Plant
FROM WLL17 INNER JOIN CC ON WLL17.CC = CC.CC
WHERE WLL17.CC<>"Outsourced Costs"
GROUP BY WLL17.Location;

Answer 1

尝试遵循这个策略。

SELECT WLL17.Location, 
    SUM(case when WLL17.EE = "Post Gate 60 (PV)" then CC.HR1*WLL17.Hours else null end) AS Plant,         
    SUM(case when WLL17.CC<>"Outsourced Costs"  then CC.HR1*WLL17.Hours else null end) AS Location_Name1,
    SUM(case when [Write condition here] then CC.HR1*WLL17.Hours else null end) AS Location_Name2
FROM WLL17 INNER JOIN CC ON WLL17.CC = CC.CC
GROUP BY WLL17.Location;

如何用三种不同的条件对同一列进行三次查询？

How to query the same column three times with three different conditions?

sql

ms-access

subquery