SQLクエリのアイデア
1. 2つのテーブルの異なるデータ:
采用union all函数, 每一个元素出现的次数count(num), count(num)为1的则只出现过一次,即为两表不同的
select age,count(age) from (select age from a union all select age from b) tem group by age having count(age) = 1;
2.一定期間のデータ:
SELECT id ,COUNT(*) FROM (SELECT *,row_number() over(PARTITION BY id ORDER BY dt) AS cum FROM (SELECT DISTINCT DATE(DATE) AS dt,id FROM person WHERE DATE BETWEEN DATE_ADD('2020-07-01',+0) AND DATE_ADD('2020-07-01',+4))a)b GROUP BY id HAVING COUNT(*)>=5;