UNION与交叉表where子句

Question

(SELECT *, 0 AS user FROM table1) 
UNION 
(SELECT * FROM table2 WHERE unix >= {$threemonths}) 
ORDER BY unix DESC;

我需要添加：

WHERE table2.identifier = table1.identifier或其他什么

我希望从table1获取所有内容，并且只有来自table2 identifier table1列identifier中else的{​​{1}}行。< / p>

Answer 1

请查看这是否适合您

(SELECT *, 0 AS user FROM table1) 
UNION 
(SELECT * FROM table2 WHERE unix >= {$threemonths} and exists (select 'Y' from table1 a where a.identifier = table2.identifier)) 
ORDER BY unix DESC;

Answer 2

可能是

{{1}}