这是因为其他类型都被过滤掉了——你可能把名字搞错了。
在任何情况下，您都可以使用 in :

select m.event_type, m.data,
       cast((((m.ore*60.0)+m.minuti)/60) as decimal(10,2)) as change
from mainGrid m
where username = 'marco_polo' and and
      data >= '2020-05-01' and
      data < '2020-06-01' and
      eventType in ('Change' , ''Service request', 'Servizio');

这不能解决问题。

如果要在分隔列中包含3种类型，可以编写：

select data, 
  case when eventType = 'Change'  then cast((((ore*60.0)+minuti)/60) as decimal(10,2)) else 0 end as change,
  case when eventType = 'Service request' then cast((((ore*60.0)+minuti)/60) as decimal(10,2)) else 0 end as servicerequest, 
  case when eventType = 'Servizio' then cast((((ore*60.0)+minuti)/60) as decimal(10,2)) else  0 end as servizio
from mainGrid
where username = 'marco_polo' and
   YEAR(data) = 2020 and
   MONTH(data) = 5 and
   (eventType = 'Change' or eventType = 'Service request' or eventType = 
    'Servizio')
order by data

如果要在一列中包含3种类型，可以编写：

select data, cast((((ore*60.0)+minuti)/60) as decimal(10,2)) as calcColumn
from mainGrid
where username = 'marco_polo' and
   YEAR(data) = 2020 and
   MONTH(data) = 5 and
   (eventType = 'Change' or eventType = 'Service request' or eventType = 
    'Servizio')
order by data

现在我明白了：

data          change            servicerequest    servizio
2020-05-30        0.00                  0.00          9.15
2020-05-12        0.00                  0.00          8.13
2020-05-30        0.00                 10.02          0.00

但是我想按“数据”分组：例如，在本例中，我只想看到一行data=2020-05-30。问题是，如果我简单地添加“groupbydata”，就会得到一个错误，告诉我groupby子句中没有使用others列。所以我在GROUPBY子句中添加了其他三列（eventtype、ore、minuti），如下所示：

select data, 
  case when eventType = 'Change' then cast((((ore*60.0)+minuti)/60) as decimal(10,2)) else 0 end as change,
  case when eventType = 'Service request' then cast((((ore*60.0)+minuti)/60) as decimal(10,2)) else 0 end as servicerequest, 
  case when eventType = 'Servizio' then cast((((ore*60.0)+minuti)/60) as decimal(10,2)) else  0 end as servizio
from mainGrid
where username = 'marco_polo' and
   YEAR(data) = 2020 and
   MONTH(data) = 5 and
   (eventType = 'Change' or eventType = 'Service request' or eventType = 'Servizio')
group by data, eventType, ore, minuti
order by data

但我得到了相同的结果，没有分组。
我还需要添加一个“total”列，给出每个日期的三种类型的总数。最后我想得到这样的东西：

data          change            servicerequest    servizio      total
2020-05-30        0.00                  10.02         9.15         10.15
2020-05-12        0.00                   0.00         8.13          8.13

有什么建议吗？谢谢。