创建一个额外的列与选择联盟在Mysql

Question

我有2个表：table1和table2，两个表的结构为; id - day - uniques - pageviews。我想创建一个包含uniques值的附加字段，其格式为2387|1283，同时在给定日期内总结uniques和pageviews。我有：

SELECT id, 
     day, 
     Sum(uniques) AS uniques, 
     Sum(pageviews) AS pageviews 
FROM (SELECT * 
     FROM table1 
     WHERE ` day ` >= '2016-07-21' 
       AND ` day ` <= '2016-07-22' 
     UNION 
     SELECT * 
     FROM table2 
     WHERE ` day ` >= '2016-07-21' 
       AND ` day ` <= '2016-07-22') t1 
GROUP BY ` day ` 
ORDER BY ` day ` ASC 

然而，这只是资金uniques和pageviews从2个表给定的日子，但我也需要知道确切的价值。假设我们在table1中有5个，在table2中有3个。该查询返回一个“唯一”字段值8。我还需要得到值5和3 seperately

任何帮助将节省大量的宝贵时间;）

谢谢

Answer 1

你查询请求一笔款项。也许你可以做一个GROUP_CONCAT（MySQL reference），这样该列返回由分隔符分隔的各个值。示例如下：

SELECT id, 
    day, 
    SUM(uniques)   AS uniques, 
    GROUP_CONCAT(CONCAT(uniques, ':', `tablename`) SEPARATOR '|') AS uniques_values, 
    SUM(pageviews)   AS pageviews, 
    GROUP_CONCAT(CONCAT(pageviews, ':', `tablename`) SEPARATOR '|') AS pageviews_values 
FROM (SELECT * , 'table1' as `tablename` 
     FROM table1 
     WHERE day >= '2016-07-21' 
       AND day <= '2016-07-22' 
     UNION 
     SELECT * , 'table2' as `tablename` 
     FROM table2 
     WHERE day >= '2016-07-21' 
       AND day <= '2016-07-22') t1 
GROUP BY day 
ORDER BY day ASC 

希望帮助:)