标签：MySQL

示例代码如下

SELECT * FROM article WHERE id IN(12,2,11) ORDER BY FIND_IN_SET(id,'12,2,11');

示例代码如下

SELECT
    *
FROM
    (
        SELECT 1 AS t_type, title, inputtime FROM table1
    UNION
        SELECT 2 AS t_type, title, inputtime FROM table2
    ) AS a
ORDER BY
     inputtime DESC
LIMIT 0, 4;

查完后会多出一列t_type表示数据来自哪个表

在数据量较小的情况下测试过; 没有在大数据量下进行测试.