从田地

Question

获得最大值和最小值我有两个表：

First: 
id | title 
1 | aaa 
2 | bbb 
3 | ccc 

Second: 
id | first_id | one | two | three | four 
1 | 1  | 3 | 1 | 4  | 6 
2 | 2  | 4 | 4 | 1  | 2 
3 | 3  | 1 | 2 | 3  | 4 

，我想显示：

id | title | min | max 
1 | aaa | 1 | 6 
2 | bbb | 1 | 4 
3 | ccc | 1 | 4 

这可能与SQL？怎么样？ :)

Answer 1

读汤姆的答案，这将是最好的事情。

反正和耻辱对我道：

SELECT f.id, f.title 
MIN(LEAST(s.one, s.two, s.three, s.four)) as min, 
MAX(GREATEST(s.one, s.two, s.three, s.four)) as max 
FROM First f 
INNER JOIN Second s on f.id = s.first_id 
GROUP BY f.id, f.title 

你可以（通过与集团）删除MIN和MAX如果二不能有相同的first_id多行。

Answer 2

规范化您的数据库。用你目前的设置不是不可能的，但绝对不推荐。

CNC中
如果你一定要，你可以使用LEAST()和GREATEST()

-edit2-

SELECT 
    a.id, 
    a.title, 
    LEAST(b.one,b.two,b.three,b.four) min, 
    GREATEST(b.one,b.two,b.three,b.four) max 
FROM first a 
INNER JOIN second b ON a.id=b.first_id 

Answer 3

你可以使用UNION来做到这一点。试试这个：

SELECT a.id, a.title, MIN(b.c) `Min`, MAX(b.c) `Max` 
FROM First a INNER JOIN 
(
    SELECT first_id, `one` c FROM `Second` 
     UNION 
    SELECT first_id, `two` c FROM `Second` 
     UNION 
    SELECT first_id, `three` c FROM `Second` 
     UNION 
    SELECT first_id, `four` c FROM `Second` 
) b on a.id = b.First_ID 
GROUP BY a.id 

SEE DEMO HERE

Answer 4

select first_id,F.title ,MIN(num) [min],MAX(num) [max] from (
select first_id,[one] [num]from [Second] union all 
select first_id,[two] [num]from [Second] union all 
select first_id,[three] [num]from [Second] union all 
select first_id,[four] [num] from [Second])[Second] 
join [First] F 
on Id=first_id 
group by first_id,F.title