从计数中添加来自UNION的值

Question

我正在尝试将匹配的id的values_occurrence加在一起。例如，ID号1具有3而另一个记录显示ID号1具有4.我想基于ID匹配来添加3 + 4。

我试图查看哪个ID在每个表中的条目最多，然后将它们一起添加。

ID  value_occurrence
--------------------
1    3
1    4

到目前为止，这就是我所拥有的。

SELECT ID, COUNT(ID) AS value_occurrence 
FROM     TABLE1
GROUP BY ID
UNION 
SELECT ID, COUNT(ID) AS value_occurrence 
FROM     TABLE2
GROUP BY ID
ORDER BY ID ASC;

任何帮助将不胜感激。

Answer 1

执行union all然后汇总：

select id, count(*) as total_cnt, sum(t1) as t1_cnt, sum(t2) as t2_cnt
from ((select id, 1 as t1, 0 as t2 from table1) union all
      (select id, 0, 1 from table2)
     ) t
group by id
order by id;