0

询问：

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

此查询在表 tabell_med_nummer 中选择一个以“0”结尾的数字。例如，它将选择 1000、1010、1020，但不会选择 1001、1002 等。

我需要基于此获得一个范围。例如 1000-1100 或 1010-1023。范围的大小是可变的。它以什么结尾并不重要，但它必须选择一个以“0”结尾的数字，例如1010。

棘手的部分是表中并非每个数字都存在。因此，如果表中不存在 1004，则结束我需要 100 的范围，它不能从 1000 开始。

有谁知道我该如何解决这个问题？

按照要求：

    +----+-------------+-------+-------+-------------------------------+---------------+---------+------+------+---------------------------------+
| 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 where 语句：

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
4

2 回答 2

2 
-- 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不能保证是唯一的，例如带有UNIQUE约束，那么您将需要替换COUNT(*)为性能较差的COUNT(DISTINCT t3.nummer)或者替换t3为(SELECT DISTINCT nummer FROM tabell_med_nummer).

于 2012-11-26T09:29:07.210 回答
1

WHERE在您的子句中添加另一个条件。

 SELECT nummer
   FROM tabell_med_nummer
  WHERE SUBSTR(nummer, -1) = 0 AND
        nummer BETWEEN 1000 AND 1100
于 2012-11-26T08:11:13.370 回答