Question

我有一个简单的查询，我想为每个联盟设置一个组。

SELECT
    model, 
    model_id
FROM
    erk
WHERE
    5000 between `min` and `max`
UNION ALL
SELECT
    model,
    model_id
FROM
    erk2
WHERE
    15000 between `min` and `max`

结果如下：

model_id   model
1           20
2           40
3           60
6           150
7           200
8           250
9           300

所以，我想显示每个值的结果（5000和15000）例如，首先使用值5000选择带来模型20,40,60。第二个选择带来150,200,250,300

我是否应该使用下面的sql设置额外的列，并确认从哪个选择中提取了哪些结果？

model_id   model   group
1           20      1
2           40      1
3           60      1
6           150     2
7           200     2
8           250     2
9           300     2

设置组ID我能够知道哪一行来自哪个选择..或者可能还有另一种方法可以识别它？

Answer 1

您只需将组添加为具有常量值的字段：

SELECT
    model, 
    model_id,
    1 as result_group
FROM
    erk
WHERE
    5000 between `min` and `max`
UNION ALL
SELECT
    model,
    model_id,
    2 as result_group
FROM
    erk2
WHERE
    15000 between `min` and `max`

Answer 2

使用此

  SELECT
        model, 
        model_id,
        1 AS `group`
    FROM
        erk
    WHERE
        5000 between `min` and `max`
    UNION ALL
    SELECT
        model,
        model_id,
        2 AS `group`
    FROM
        erk2
    WHERE
        15000 between `min` and `max`

是否可以在MYSQL上设置每个UNION的组？

2 个答案: