SQL: 如何动态解析从最小到下一分钟的范围？

Question

我想弄清楚如何（或看看是否可能）我可以获取 'TEST' 的最小值并获取 'TEST' 的下一个最小值，然后再次加入并继续第二个最小值，等等，等等

表 1

ID  TEST
A12 1
A12 2
A12 3
A12 5
A12 8
B35 1
B35 3

我想要的结果：

ID  RANGE1  RANGE2
A12 1   2
A12 2   3
A12 3   5
A12 5   8
B35 1   3

table 我使用的代码：

WITH FRED AS
(
SELECT  'A12' AS ID
    , 1 AS TEST
UNION
SELECT  'A12' AS ID
    , 2 AS TEST
UNION   
SELECT  'A12' AS ID
    , 3 AS TEST
UNION   
SELECT  'B35' AS ID
    , 1 AS TEST
UNION   
SELECT  'B35' AS ID
    , 2 AS TEST
)
SELECT  *
FROM    FRED F

Answer 1

这对我有用：

--Construct sample data.
WITH FRED AS
(
SELECT  'A12' AS ID
    , 1 AS TEST
UNION
SELECT  'A12' AS ID
    , 2 AS TEST
UNION   
SELECT  'A12' AS ID
    , 3 AS TEST
UNION
SELECT  'A12' AS ID
    , 5 AS TEST
UNION
SELECT  'A12' AS ID
    , 8 AS TEST
UNION   
SELECT  'B35' AS ID
    , 1 AS TEST
UNION   
SELECT  'B35' AS ID
    , 3 AS TEST
),

--This is the sample data
test_data AS
(
SELECT  *
FROM    FRED F
ORDER BY ID, TEST
)

SELECT  td.ID, td.TEST as RANGE1, MIN(td2.TEST) as RANGE2

FROM    test_data td
    cross join test_data td2

WHERE   td.ID = td2.ID
    AND
    td.TEST < td2.TEST

GROUP BY    td.ID, td.TEST

ORDER BY td.ID, td.TEST

test_data给出了你提供的样本。一旦你让我们都知道你希望如何处理这些价值案例，我就可以尝试处理重复的价值案例。上面的当前代码没有这样做。

Answer 2

假设这是 mysql（但大多数其他 DBMS 也会这样做），您可以将 table 与其自身连接起来，并在 ON 子句中使用限制。

最小值和分组可以帮助你。

例如：

mysql> SELECT m.id, m.test AS RANGE1 ,min(mm.test) AS RANGE2 
       FROM table1 AS m
       INNER JOIN table1 AS mm ON m.id=mm.id AND mm.test > m.test 
       GROUP BY m.id,m.test;
+------+--------+--------+
| id   | RANGE1 | RANGE2 |
+------+--------+--------+
| a12  |      1 |      2 |
| a12  |      2 |      3 |
| a12  |      3 |      5 |
| a12  |      5 |      8 |
| b35  |      1 |      3 |
+------+--------+--------+
5 rows in set (0.00 sec)

注意这些事情的效率。

您可能需要研究如何处理 table 中不存在第二个值的边缘情况。

另见此处：https://dba.stackexchange.com/questions/24014/how-do-i-get-the-current-and-next-greater-value-in-one-select

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