我正在尝试编写一个select查询来在mysql中创建一个视图。视图中的每一行都应该显示从多个表中收集的用户值的每周摘要（sum，avg）。这些表彼此相似，但不完全相同。视图还应该包括行，以防其他表没有该周的值。像这样：

| week_year | sum1 | avg1 | sum2 | user_id |
| --------- | ---- | ---- | ---- | ------- |
| 201840    |      |      | 3    | 1       |
| 201844    | 45   | 55   |      | 1       |
| 201845    | 55   | 65   |      | 1       |
| 201849    | 65   | 75   |      | 1       |
| 201849    | 75   | 85   | 3    | 2       |

表（简化）如下：

CREATE TABLE IF NOT EXISTS `t1` (
  `user_id` INT NOT NULL AUTO_INCREMENT,
  `date` DATE NOT NULL,
  `value1` int(3) NOT NULL,
  `value2` int(3) NOT NULL,
  PRIMARY KEY (`user_id`,`date`)
) DEFAULT CHARSET=utf8;

CREATE TABLE IF NOT EXISTS `t2` (
  `id` INT NOT NULL AUTO_INCREMENT,
  `date` DATE NOT NULL,
  `value3` int(3) NOT NULL,
  PRIMARY KEY (`id`)
) DEFAULT CHARSET=utf8;

CREATE TABLE IF NOT EXISTS `t3` (
  `t3_id` INT NOT NULL,
  `user_id` INT NOT NULL
) DEFAULT CHARSET=utf8;

我当前的解决方案似乎不合理，我不确定它在数千行的情况下会如何执行：

select ifnull(yearweek(q1.date1), yearweek(q1.date2)) as week_year,
       sum(value1)                             as sum1,
       avg(value2)                              as avg1,
       sum(value3)                                   as sum2,
       q1.user_id
from (select t2.date as date2,
             t1.date as date1,
             ifnull(t3.user_id, t1.user_id) as user_id,
             t1.value1,
             t1.value2,
             t2.value3
      from t2
             join t3 on t3.t3_id=t2.id
             left join t1 on yearweek(t1.date) = yearweek(t2.date) and t1.user_id = t3.user_id
      union
      select t2.date as date2,
             t1.date as date1,
             ifnull(t3.user_id, t1.user_id) as user_id,
             t1.value1,
             t1.value2,
             t2.value3
      from t2
             join t3 on t3.t3_id=t2.id
             right join t1 on yearweek(t1.date) = yearweek(t2.date) and t1.user_id = t3.user_id) as q1

group by week_year, user_id;

小提琴
当前的解决方案在性能方面还可以吗？还是有更好的选择？如果将来添加第三个（或第四个）表，我将如何管理查询？我应该考虑创建一个单独的表，用触发器更新吗？
提前谢谢。