Question

查询：

SELECT nummer
   FROM tabell_med_nummer
  WHERE SUBSTR(nummer, -1) = 0

此查询选择表tabell_med_nummer中以“0”结尾的数字。例如，它将选择1000,1010,1020，但不选择1001,1002等。

我需要根据这个得到一个范围。例如1000-1100或1010-1023。范围的大小是可变的。它的结尾并不重要，但它必须选择一个以“0”结尾的数字，如1010。

棘手的部分是表中不存在每个数字。因此，如果表格中不存在1004，那么我需要100的范围，它不能从1000开始。

有谁知道如何解决这个问题？

根据要求：

    +----+-------------+-------+-------+-------------------------------+---------------+---------+------+------+---------------------------------+
| id | select_type | table | type  | possible_keys                 | key           | key_len | ref  | rows | Extra                           |
+----+-------------+-------+-------+-------------------------------+---------------+---------+------+------+---------------------------------+
|  1 | SIMPLE      | f     | ALL   | NULL                          | NULL          | NULL    | NULL |   19 | Using temporary; Using filesort |
|  1 | SIMPLE      | t2    | index | telefonnummer,telefonnummer_2 | telefonnummer | 5       | NULL | 1001 | Using index; Using join buffer  |
|  1 | SIMPLE      | p     | ALL   | NULL                          | NULL          | NULL    | NULL | 4568 | Using where; Using join buffer  |
|  1 | SIMPLE      | t3    | index | telefonnummer,telefonnummer_2 | telefonnummer | 5       | NULL | 1001 | Using index; Using join buffer  |
|  1 | SIMPLE      | t1    | ALL   | telefonnummer,telefonnummer_2 | NULL          | NULL    | NULL | 1001 | Using where; Using join buffer  |
+----+-------------+-------+-------+-------------------------------+---------------+---------+------+------+---------------------------------+
5 rows in set (0.00 sec)

我更改了一些表和字段名称，并添加了一些连接和法规：

SELECT t1.telefonnummer start, t2.telefonnummer end, t1.kundenummer kundenummer, t1.fornavn fornavn, t1.etternavn etternavn, t1.bedriftsnavn bedriftsnavn, t1.organisasjonsnummer organisasjonsnummer, t1.partnerID partnerID

FROM TELEFONNUMMERTILDELING t1

JOIN TELEFONNUMMERTILDELING t2
ON t1.telefonnummer % 10 = 0
AND t1.telefonnummer <= t2.telefonnummer

JOIN TELEFONNUMMERTILDELING t3
ON t3.telefonnummer BETWEEN t1.telefonnummer AND t2.telefonnummer

JOIN TELEFONNUMMERTILDELING_POSTNUMMER p
ON p.postnummer = 4085

JOIN TELEFONNUMMERTILDELING_FYLKE f
ON f.ID = p.fylkeID GROUP BY start, end

HAVING end - start + 1 = COUNT(*)
AND end - start + 1 = 50
AND (kundenummer IS NULL OR kundenummer = '')
AND (fornavn IS NULL OR fornavn = '')
AND (etternavn IS NULL OR etternavn = '')
AND (bedriftsnavn IS NULL OR bedriftsnavn = '')
AND (organisasjonsnummer IS NULL OR organisasjonsnummer = '')
AND partnerID = 1001

Answer 1

-- get the start and end points
SELECT   t1.nummer AS start, t2.nummer AS end

-- pair every possible start number with every potential end number
FROM     tabell_med_nummer t1
    JOIN tabell_med_nummer t2
      ON t1.nummer % 10 = 0 AND t1.nummer <= t2.nummer

-- obtain every number in between
    JOIN tabell_med_nummer t3
      ON t3.nummer BETWEEN t1.nummer AND t2.nummer

-- group into potential ranges
GROUP BY start, end

-- now limit only to contiguous ranges
  HAVING end - start + 1 = COUNT(*)

-- and those that contain the desired number of records
     AND end - start + 1 = ?

如果nummer不能保证唯一，例如如果使用UNIQUE约束，则需要将COUNT(*)替换为性能较低的COUNT(DISTINCT t3.nummer)，否则将t3替换为(SELECT DISTINCT nummer FROM tabell_med_nummer)。

Answer 2

在WHERE子句中添加其他条件。

 SELECT nummer
   FROM tabell_med_nummer
  WHERE SUBSTR(nummer, -1) = 0 AND
        nummer BETWEEN 1000 AND 1100

选择一个数字范围

2 个答案: