一种方法是分别对结果求和，使用已启动的相同条件聚合，然后 UNION 把结果放在一起。由于第一列在其他任何地方都不存在，因此必须将其硬编码到查询中。

SELECT 
    'TotalPayloadGb' AS SumOf,
    sum(CASE WHEN t.BTS_TYPE = '2G' THEN s.TotalPayloadGb ELSE 0 END) AS [Total 2G],
    sum(CASE WHEN t.BTS_TYPE = '3G' THEN s.TotalPayloadGb ELSE 0 END) AS [Total 3G],
    sum(CASE WHEN t.BTS_TYPE = '4G' THEN s.TotalPayloadGb ELSE 0 END) AS [Total 4G]
FROM sitetable AS s
INNER JOIN techtable AS t
    ON s.sitename = t.sitename
UNION
SELECT 
    'SumTCHTraffic' AS SumOf,
    sum(CASE WHEN t.BTS_TYPE = '2G' THEN s.SumTCHTraffic ELSE 0 END) AS [Total 2G],
    sum(CASE WHEN t.BTS_TYPE = '3G' THEN s.SumTCHTraffic ELSE 0 END) AS [Total 3G],
    sum(CASE WHEN t.BTS_TYPE = '4G' THEN s.SumTCHTraffic ELSE 0 END) AS [Total 4G]
FROM sitetable AS s
INNER JOIN techtable AS t
    ON s.sitename = t.sitename;

根据您要做的事情，您可以这样做：

SELECT tt.BTS_Type, sum(st.TotalPayloadDb)
 FROM SiteTable st
    INNER JOIN TechTable as tt on st.sitename = tt.sitename

这将为每个bts\U类型值提供一行。