我需要的是获得国籍，月份和月份以及每个国籍

Question

SELECT DISTINCT 
    subnationality, 
    CONVERT(varchar(3), SubDate) as months,
    COUNT(CONVERT(varchar(3), SubDate)) 
FROM
    xxx
WHERE
    CONVERT(varchar(3), SubDate) IN (SELECT CONVERT(varchar(3), SubDate) AS months  
                                     FROM xxx
                                     WHERE DATEPART(yyyy, SubDate) = 2017
                                     GROUP BY CONVERT(varchar(3), SubDate))