MySQL

Question

已更新：

TABLE: 我的数据

    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，该查询将 return 基于 CUST_DATE 的每组 ID 中 CURRENT 的第一个和最后一个值。

要指出的几点：

我在这个例子中只显示了两个 ID。真正的 table 有成千上万个不同的 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得不正常.您可以在上面 table 中的 ID 16 上看到此问题。

两天来我一直在思考这个看似简单的查询...只是无法理解它。

预期输出（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，所以我假设您想要所有这些，因为您没有另外指定...

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);

自从第一次提出这个问题后，规范发生了重大变化。新要求太明显了，不用理会。

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

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

MySQL - get min and max values for id's in group

join

self