Question

所以，我有一张包含一些独特数字的表格。

假设范围是1到1000。

我想做一个选择查询，获取给定范围内的最低空闲数。

所以，例如：where number > 10 and number < 200。如果此范围内没有数字，我想返回10。

如果恰好在此范围内有数字11,12,13, 15, 16。我想返回14。

我正在尝试类似下面的内容，但无济于事。

SELECT MIN(number)
FROM 
(SELECT 10 number  
UNION 
SELECT number+1 FROM table) a
WHERE number < 200 AND number 
NOT IN (SELECT number FROM table);

感谢。

Answer 1

SELECT IFNULL(MIN(t1.n) + 1, 10)
  FROM (SELECT n
          FROM t
         WHERE n > 10   # lower bound, exclusive
           AND n < 199  # upper bound, inclusive
     UNION ALL
        SELECT 10) t1
  LEFT JOIN t t2
    ON t2.n = t1.n + 1
 WHERE t2.n IS NULL;

SQL Fiddle

Answer 2

生成一系列数字（在本例中为1到1000）并将LEFT JOIN加入到您的表中并找到不匹配的数字。使用MIN从表中找不到的生成范围中获取最小数字。

SELECT MIN(iNum)
FROM
(
    SELECT 1 + units.i + tens.i * 10 + hundreds.i * 100 AS iNum
    FROM (SELECT 0 i UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9)units
    CROSS JOIN (SELECT 0 i UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9)tens
    CROSS JOIN (SELECT 0 i UNION SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5 UNION SELECT 6 UNION SELECT 7 UNION SELECT 8 UNION SELECT 9)hundreds
) a
LEFT OUTER JOIN table b
ON a.iNum = b.number
WHERE a.iNum BETWEEN 10 AND 200
AND b.number IS NULL

MySQL Query不在表格范围内的最低值

2 个答案: