2018-05-19 mssql 的select from （select from )使用的限制

可以使用，可以运行，

但是 要给 （select from） as alias 别名（e.g kk） ，加别名可用。 

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select

kk.OlympicYear,

kk.Country

from

(

select

sum(Gold_Medals) as Total_GM,

sum(Silver_Medals)as Total_SM,

sum(Bronze_Medals) as Total_BM,

sum(Gold_Medals + Silver_Medals + Bronze_Medals) as Total_Medals,

main.OlympicYear,

main.Country

from OlympicAthletes as main

left join (

select

AthleteID,

Athlete,

CONVERT(VARCHAR(10),  Closing_Ceremony_Date, 101) as formatdate,

(3*Gold_Medals + 2*Silver_Medals + Bronze_Medals)as Medal_Weight,

OlympicYear,

Country

from OlympicAthletes

) as minor

on main.OlympicYear = minor.OlympicYear and main.Country = minor.Country

group by main.OlympicYear,main.Country

) as kk