从2张桌子获得平均值？

Question

我需要帮助sql命令〜 感谢您的帮助^^

所以我有2张桌子

如何从这2张表中获得平均值。

我想要的结果是

Country Code 65 has 49.5 Frequency
Country Code 42 has 17 Frequency
Country Code 33 has 18 Frequency
Country Code 11 has 5 Frequency

非常感谢！

Answer 1

您可以将这两个表作为UNION ALL进行查询，然后将其用作GROUP BY列上AVG()和Frequency的子查询：

select cntry_cde, Avg(freq) as freq_avg
from 
(
    select t1.cntry_cde, t1.freq
    from avg_call t1
    union all
    select t2.cntry_cde, t2.freq
    from calls_at_one t2
)
group by cntry_cde;