Question

我有一个包含整数列的表，名为“Day1Reg”，“Day2Reg”，......“Day7Reg”，“Day1OT”，“Day2OT”，......“Day7OT”。我想选择表中的所有行，计算2个名为“WkReg”和“WkOT”的新列，它们将是DayxReg和DayxOT的总和。 Dayx列可能为null。这是迄今为止的查询：

select
  *,
  (Day1Reg+Day2Reg+Day3Reg+Day4Reg+Day5Reg+Day6Reg+Day7Reg) as WkReg,
  (Day1OT+Day2OT+Day3OT+Day4OT+Day5OT+Day6OT+Day7OT) as WkOT
from
  Week01
where
  UserName = "JustMe"

创建了WkReg和WkOT列，但没有值。在几个Dayx列中有整数值。不返回任何错误，只返回WkReg和WkOT中的空白值。

Answer 1

据推测，某些整数值为NULL，这导致整个总和为NULL。您可以使用coalesce()将值替换为0：

select w.*
       (coalesce(Day1Reg, 0) + coalesce(Day2Reg, 0) + coalesce(Day3Reg, 0) +
        coalesce(Day4Reg, 0) + coalesce(Day5Reg, 0) + coalesce(Day6Reg, 0) + coalesce(Day7Reg, 0)
       ) as WkReg,
       (coalesce(Day1OT, 0) + coalesce(Day2OT, 0) + coalesce(Day3OT, 0) +
        coalesce(Day4OT, 0) + coalesce(Day5OT, 0) + coalesce(Day6OT, 0) + coalesce(Day7OT, 0)
       ) as WkOT
from Week01 w
where w.UserName = 'JustMe';

Answer 2

UPDATE `Week01` SET `WkReg` = (Day1Reg+Day2Reg+Day3Reg+Day4Reg+Day5Reg+Day6Reg+Day7Reg), 
`WkOT`=(Day1OT+Day2OT+Day3OT+Day4OT+Day5OT+Day6OT+Day7OT) 
WHERE `UserName` = "JustMe"

基于整数字段计算新列

2 个答案: