如何在mysql中找到没有间隙的序列号？

考虑一个具有列serialnumber的表productSerialnumber。此列获取产品的单个序列号

产品A的序列号从101到109，然后是111到119和139到150。例如，序列号110和120-138不可用

我想有一个查询或东西，可以返回连续序列号集。 例如，结果将是

from       to 
=======    ====
101        109
111        119
139        150

需要考虑的是，这个表有超过一百万行的庞大数据集

任何帮助都会得到真正的赏识

有更多的发挥：-

SELECT MIN(aFirstSerial), MAX(aLastSerial)
FROM
(
    SELECT @FirstSerial:=IF(productSerialnumber = @LastSerial + 1, IF(@FirstSerial = 0, productSerialnumber, @FirstSerial), productSerialnumber) AS aFirstSerial, 
        @RangeNum:=IF(productSerialnumber = @LastSerial + 1, @RangeNum, @RangeNum + 1) AS aRangeNum, 
        @LastSerial := productSerialnumber AS aLastSerial
    FROM
    (
        SELECT productSerialnumber
        FROM Product
        ORDER BY productSerialnumber
    ) Sub1
    CROSS JOIN (SELECT @PrevSerial:=0, @RangeNum:=0, @FirstSerial:=0, @LastSerial:=0) Sub2
) Sub3
GROUP BY aRangeNum

SQL在这里为它摆弄：-

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我认为这是非常快的，因为我们避免了连接，只对数据进行一次迭代。唯一的瓶颈是我们使用2个临时表，并且需要使用用户定义的值

无集合语句

With Set语句

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SQLFiddle:

Minor mod修复meze发现的边缘案例问题+1我尝试了这个，它是迄今为止最快的：-）。测试：您是否尝试了数据集上的查询。有结果吗？

select START_INTERVAL+0, END_INTERVAL+0
from
(
  select 
  if(@start = NULL or @start > PRODUCTSERIALNUMBER, @start='', '') as SET_START,
  if (@start = '', @start:= @previous, @start) as START_INTERVAL,
  if(PRODUCTSERIALNUMBER - @previous > 1, concat(@end:=@previous,@start:=''), @end:='') as END_INTERVAL,
  @previous:= PRODUCTSERIALNUMBER as PRODUCTSERIALNUMBER
  from 
  (
    select min(PRODUCTSERIALNUMBER)-2 as PRODUCTSERIALNUMBER from Product
    UNION
    (select PRODUCTSERIALNUMBER as PRODUCTSERIALNUMBER from Product ORDER BY productSerialnumber)
    UNION
    select max(PRODUCTSERIALNUMBER)+2 as PRODUCTSERIALNUMBER from Product    
  ) as TEMP
)
as RESULTS where 
not START_INTERVAL is null AND
not END_INTERVAL is null AND
not END_INTERVAL = '' AND
not START_INTERVAL - END_INTERVAL > 0;

set @start='';

select select START_INTERVAL+0, END_INTERVAL+0
from
(
  select 
  if (@start = '', @start:= @previous, @start) as START_INTERVAL,
  if(PRODUCTSERIALNUMBER - @previous > 1, concat(@end:=@previous,@start:=''), @end:='') as END_INTERVAL,
  @previous:= PRODUCTSERIALNUMBER as PRODUCTSERIALNUMBER
  from 
  (
    select min(PRODUCTSERIALNUMBER)-2 as PRODUCTSERIALNUMBER from Product
    UNION
    (select PRODUCTSERIALNUMBER as PRODUCTSERIALNUMBER from Product ORDER BY productSerialnumber)
    UNION
    select max(PRODUCTSERIALNUMBER)+2 as PRODUCTSERIALNUMBER from Product    
  ) as TEMP
)
as RESULTS where 
not RESULTS.START_INTERVAL is null AND
not RESULTS.END_INTERVAL is null AND
not RESULTS.END_INTERVAL = '' AND
not RESULTS.START_INTERVAL - RESULTS.END_INTERVAL > 0;