Question

更新：

表：mydata

    id    trans_id  CURRENT   CUST_DATE   
    ------------------------------------
    16    2362      152.40    2015-05-11
    16    2363      146.80    2015-05-26
    16    1669      147.00    2015-06-16
    16    1979      148.60    2015-07-06
    16    2344      144.00    2015-08-06
    104   1280      161.40    2015-05-29
    104   1553      158.20    2015-06-10
    104   1898      158.20    2015-06-29
    104   2131      158.20    2015-07-15
    104   2223      158.20    2015-07-27
    104   2294      158.20    2015-08-03

我需要一个查询，它将根据CUST_DATE在每组ID中返回CURRENT的第一个和最后一个值。

要指出的一些项目：

我在这个例子中只显示了两个ID。真正的表有数千个不同的ID。
trans_id是一个自动递增的字段。我的初始查询有max（trans_id）和min（trans_id）...这一直有效，直到添加了一个具有较早日期值的新行并导致自然升序变为不合时宜。您可以在上表中的ID 16上看到此问题。

我已经用这个看似简单的查询了两天了......只是无法绕过它。

预期产出（扁平结构）：

    id    CURRENT_MAX  CURRENT_MIN   
    -------------------------------
    16    152.40       144.00
    104   161.40       158.20

Answer 1

几行共享相同的最小电流，所以我假设你想要所有这些，因为你没有另外指定......

DROP TABLE IF EXISTS my_table;

 CREATE TABLE my_table
 (id    INT NOT NULL
 , trans_id  INT NOT NULL 
 ,CURRENT   DECIMAL(5,2)
 ,CUST_DATE   DATE NOT NULL
 );

 INSERT INTO my_table VALUES
 (16   ,2362      ,152.40    ,'2015-05-11'),
 (16   ,2363      ,146.80    ,'2015-05-26'),
 (16   ,1669      ,147.00    ,'2015-06-16'),
 (16   ,1979      ,148.60    ,'2015-07-06'),
 (16   ,2344      ,144.00    ,'2015-08-06'),
 (104  ,1280      ,161.40    ,'2015-05-29'),
 (104  ,1553      ,158.20    ,'2015-06-10'),
 (104  ,1898      ,158.20    ,'2015-06-29'),
 (104  ,2131      ,158.20    ,'2015-07-15'),
 (104  ,2223      ,158.20    ,'2015-07-27'),
 (104  ,2294      ,158.20    ,'2015-08-03');

SELECT a.*
  FROM my_table a
  JOIN
     (
       SELECT id, MAX(current) x_current FROM my_table GROUP BY id
       UNION
       SELECT id, MIN(current) x_current FROM my_table GROUP BY id
     ) b
    ON b.id = a.id AND b.x_current = a.current;
  +-----+----------+---------+------------+
  | id  | trans_id | CURRENT | CUST_DATE  |
  +-----+----------+---------+------------+
  |  16 |     2362 |  152.40 | 2015-05-11 |
  |  16 |     2344 |  144.00 | 2015-08-06 |
  | 104 |     1280 |  161.40 | 2015-05-29 |
  | 104 |     1553 |  158.20 | 2015-06-10 |
  | 104 |     1898 |  158.20 | 2015-06-29 |
  | 104 |     2131 |  158.20 | 2015-07-15 |
  | 104 |     2223 |  158.20 | 2015-07-27 |
  | 104 |     2294 |  158.20 | 2015-08-03 |
  +-----+----------+---------+------------+

或

 SELECT a.*
   FROM my_table a
   JOIN
      (
        SELECT id
             , MAX(current) max_current
             , MIN(current) min_current 
          FROM my_table 
         GROUP  
            BY id
      ) b
     ON b.id = a.id AND a.current IN (b.max_current,b.min_current);

自首次提出此问题以来，规范发生了重大变化。新要求太明显了，无法理解。

Answer 2

SQL Fiddle

MySQL 5.6架构设置：

CREATE TABLE mydata
    (`id` int, `trans_id` int, `CURRENT` double, `CUST_DATE` datetime)
;

INSERT INTO mydata
    (`id`, `trans_id`, `CURRENT`, `CUST_DATE`)
VALUES
    (16, 2362, 152.40, '2015-05-11 00:00:00'),
    (16, 2363, 146.80, '2015-05-26 00:00:00'),
    (16, 1669, 147.00, '2015-06-16 00:00:00'),
    (16, 1979, 148.60, '2015-07-06 00:00:00'),
    (16, 2344, 144.00, '2015-08-06 00:00:00'),
    (104, 1280, 161.40, '2015-05-29 00:00:00'),
    (104, 1553, 158.20, '2015-06-10 00:00:00'),
    (104, 1898, 158.20, '2015-06-29 00:00:00'),
    (104, 2131, 158.20, '2015-07-15 00:00:00'),
    (104, 2223, 158.20, '2015-07-27 00:00:00'),
    (104, 2294, 158.20, '2015-08-03 00:00:00')
;

查询1 ：

SELECT id, MIN(CURRENT), MAX(CURRENT) 
FROM mydata
GROUP BY ID

<强> Results ：

|  id | MIN(CURRENT) | MAX(CURRENT) |
|-----|--------------|--------------|
|  16 |          144 |        152.4 |
| 104 |        158.2 |        161.4 |

MySQL - 获取组中id的最小值和最大值

2 个答案: