按表中的出現次數排序

Question

我有一個包含許多表的數據庫..並且每個表只存儲了ID。現在我想要做的是：

SELECT id FROM table1, table2, table3 
GROUP BY id; 

但我也想按降序排列。

例如，所有3個表中的ID應該出現在最上面，而只出現在一個表中的ID應該出現在底部。有關如何做到這一點的任何線索？

Answer 1

試試這個太

select id from 
(
    SELECT id FROM table1 
    union all 
    select id from table2 
    union all 
    select id from table3 
) as t 
GROUP BY id 
order by count(id) desc 

Answer 2

select id from 
(
    SELECT id FROM table1 
    union all 
    select id from table2 
    union all 
    select id from table3 
) as t 
GROUP BY id 
order by id desc 

Answer 3

select sum(t1.id IS NOT NULL,t2.id IS NOT NULL, t3.id IS NOT NULL) as total,t1.id from table1 as t1 join table2 as t2 on t1.id=t2.id join table3 as t3 on t3.id = t1.id order by total desc; 

我不知道你的問題，但是這可以幫助