如何在UNPIVOT命令中修复语法？括号为意外的语法错误

Question

由于我需要行中的日期而不是列中的日期，因此我试图取消对该表的透视。我相对较新，但我认为Unpivot应该有效。但是，它表示“语法错误”，这是意外的（在所有地方，我看到UNPIVOT命令后都有一个括号。

我尝试了其他子句来封装它，或者根本不使用它，但是总是出现相同的错误。应该使用标准SQL。

standardSQL

SELECT service_id, day, service
FROM calendar
UNPIVOT
(
    service
    FOR day in ( monday, tuesday, wednesday, thursday, friday, saturday, sunday )
) AS unpvt;

应该获得一个列表，其列标题应为：service_id，day，service

Answer 1

您可以尝试这种方式-

SELECT service_id, service, day
FROM calendar
UNPIVOT
(
    S FOR day in ( [monday], [tuesday], [wednesday], [thursday], [friday], [saturday], [sunday] )
) AS unpvt;

Answer 2

标准SQL中没有unpivot。我偏爱的方法是横向连接，但这因数据库而异。

通用方法是仅使用union all：

select service_id, 'monday' as day, monday as service
from calendar
union all
select service_id, 'tuesday' as day, tuesday as service
from calendar
union all
select service_id, 'wednesday' as day, wednesday as service
from calendar
union all
select service_id, 'thursday' as day, thursday as service
from calendar
union all
select service_id, 'friday' as day, friday as service
from calendar
union all
select service_id, 'saturday' as day, saturday as service
from calendar
union all
select service_id, 'sunday' as day, sunday as service
from calendar;