如果期望值大于999999999999999999，请尝试此操作，然后使用更高的值

select id_car,
min(least(coalesce(col_1,9999999999999999999),coalesce(col_2,9999999999999999999),coalesce(col_3,9999999999999999999),
          coalesce(col_4,9999999999999999999),coalesce(col_5,9999999999999999999),coalesce(col_6,9999999999999999999)
        )
    ) as min_val 
from your_table
group by id_car

下面的查询将为您提供所需的结果

select tab.ID_CAR, min(tab.val) as lowest_value from
(
      (select ID_CAR,min(col_1) val
      from table
      group by ID_CAR)
  union
      (select ID_CAR,min(col_2) val
      from table
      group by ID_CAR)
  union
      (select ID_CAR,min(col_3) val
      from table
      group by ID_CAR)
  union
      (select ID_CAR,min(col_4) val
      from table
      group by ID_CAR)
  union
      (select ID_CAR,min(col_5) val
      from table
      group by ID_CAR)
  union
      (select ID_CAR,min(col_6) val
      from table
      group by ID_CAR)
) tab
group by tab.ID_CAR

你需要 UNION :

select id_car, min(val) as lowest_value
from (select id_car, col_1 as Val
      from table union 
      select id_car, col_2
      from table
      . . .
     ) t 
group by id_car;

没有 union 您可以简单地组合最小值和最小值函数：

select
  ID_CAR,min(least(col_1,col_2,col_3,col_4,col_5,col_6)) lowest_value
from
  table
group by
  ID_CAR

或者如果你有 null 你需要的价值观 ifnull 或者 coalesce 功能

select
  ID_CAR,
  min(least(
    ifnull(col_1,~0),
    ifnull(col_2,~0),
    ifnull(col_3,~0),
    ifnull(col_4,~0),
    ifnull(col_5,~0),
    ifnull(col_6,~0)
  )) as lowest_value
from
  table
group by
  ID_CAR
``` `~0` 是mysql中的最大bigint
相反的功能 `least` 是 `greatest` 相反的功能 `min` 是 `max` ;-)
与mysql、oracle、postgres、hive一起使用。。。
问题2，类似这样：

select
ID_CAR,
min(least(
DATE_ADD(col_date, INTERVAL ifnull(col_1,0) DAY),
DATE_ADD(col_date, INTERVAL ifnull(col_2,0) DAY),
DATE_ADD(col_date, INTERVAL ifnull(col_3,0) DAY),
DATE_ADD(col_date, INTERVAL ifnull(col_4,0) DAY),
DATE_ADD(col_date, INTERVAL ifnull(col_5,0) DAY),
DATE_ADD(col_date, INTERVAL ifnull(col_6,0) DAY)
)) as lowest_date
from
table
group by
ID_CAR

或类似于此（除非所有列都可以为null）：

select
ID_CAR,
DATE_ADD(col_date, INTERVAL min(least(
ifnull(col_1,~0),
ifnull(col_2,~0),
ifnull(col_3,~0),
ifnull(col_4,~0),
ifnull(col_5,~0),
ifnull(col_6,~0)
)) DAY) as lowest_date
from
table
group by
ID_CAR

最简单的方法是使用最少的：

SELECT ID_CAR, least(t.col_1, t.col_2, t.col_3, t.col_4, t.col_5, t.col_6)
FROM
(SELECT ID_CAR, min(col_1) as col_1, min(col_2) as col_2, min(col_3) as col_3, min(col_4) as col_4, min(col_5) as col_5, min(col_6) as col_6
FROM YOUR_TABLE GROUP BY ID_CAR) t;

但是：如果least的任何参数为null，它将返回null。您要么需要将空值转换为一个高值（这是一个hack，但在实践中会起作用，请参阅其他答案）。
也就是说做这样的事：

SELECT ID_CAR, LEAST(col_1, col_2, col_3,
                     col_4, col_5, col_6) as l
FROM
(SELECT ID_CAR, 
   IFNULL(min(col_1), 9999)  as col_1, 
   IFNULL(min(col_2), 9999)  as col_2,
   IFNULL(min(col_3), 9999)  as col_3,
   IFNULL(min(col_4), 9999)  as col_4,
   IFNULL(min(col_5), 9999)  as col_5,
   IFNULL(min(col_6), 9999)  as col_6
FROM YOUR_TABLE GROUP BY ID_CAR) t;

但是，最好使用技巧将表转换为以下形式的三行表：

car_id | attr | value
     1      1    NULL   ; or use strings such as "size"
     1      2     250