mysql - 有IN子句时如何使用UNION ALL？

Question

我有这样的查询:

select p.title
from Posts p
where p.id in (select id from Votes where timestamp between $x and $y);

现在想用这个表代替 Posts:

select title from Posts1
union all
select title from Posts2

如何在第一个查询中写这个 ^ 而不是 Posts？

Answer 1

尝试下面的查询，希望它会表现得更好-

SELECT p.title FROM Posts1 p JOIN votes v ON p.id=v.id
WHERE v.timestamp BETWEEN $X AND $Y
UNION ALL 
SELECT p.title FROM Posts2 p JOIN votes v ON p.id=v.id
WHERE v.timestamp BETWEEN $X AND $Y;