MySQL:找出丢失的订单 ID

Question

我知道这个问题在 StackOverFlow 中问了好几次。我试过其中的几个，但我运气不好。

我有一个 MySQL 表，其中有一个字段 (orders_id) 可能会随机出现在表中(不按顺序)，我需要找出表中缺少哪些 ID。

 orders_id     product_name       qty    
       1007      Wireless Mouse      1
       1000      Laptop              1
       1004      Wireless Mouse      3
       1020      PC                  3
       1003      Wireless Mouse      4
       1025      IPAD                4
       1026      iphone              1

Expected Answer:

Assume orders_id start from 1000.

  orders_id     
       1000 
       1001
       1002     
       1005      
       1006    
       1008      
      ......  

i have already created above table at "SqlFiddle" , you guys can use it.

See table: SQLfiddle

**the SQL i have tried: **

declare @id int
declare @maxid int

set @id = 1
select @maxid = max(`orders_id`) from orders

create temporary table IDSeq
(
    id int
)

while @id < @maxid
begin
    insert into IDSeq values(@id)

    set @id = @id + 1
end

select 
    s.id 
from 
    idseq s 
    left join orders t on 
        s.id = t.`orders_id` 
 where t.`orders_id` is null

 drop table IDSeq

我从以下答案中获取了上述 SQL:

SQL: find missing IDs in a table

我也尝试过 ANSI SQL:

SELECT a.orders_id+1 AS start, MIN(b.orders_id) - 1 AS end
    FROM orders AS a, orders AS b
    WHERE a.orders_id < b.orders_id
    GROUP BY a.orders_id
    HAVING start < MIN(b.orders_id)

有人知道吗？我怎样才能找到丢失的订单 ID。

Answer 1

这是另一种解决方案:

CREATE TABLE TEMP 
(n int);
INSERT INTO Temp VALUES(0),(1),(2),(3),(4),(5),(6),(7),(8),(9);

SET @maxid = (SELECT MAX(orders_id) FROM orders);

SELECT     s.id 
FROM
(
    SELECT id
    FROM
    (
       SELECT t4.n * 1000 + t3.n * 100 + t2.n * 10 + t1.n + 1 AS id
       FROM         TEMP AS t1
       CROSS JOIN TEMP AS t2
       CROSS JOIN TEMP AS t3
       CROSS JOIN TEMP AS t4
    ) t 
    WHERE id BETWEEN 1000 AND @maxid
) s 
LEFT JOIN orders t ON s.id = t.`orders_id` 
WHERE t.`orders_id` IS NULL;

这应该为您提供 orders_id:

ID
1001
1002
1005
1006
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1021
1022
1023
1024

SQL Fiddle Demo

请注意:我创建了一个包含 0 到 9 值的 TEMP 表，以便用于生成包含 1 到 10000 值的 anchor 表而不是while 循环，你在你发布的查询中。您可以根据表中的值控制此表中的值。如果您的值超过 10000 CROSS JOIN，则再对 TEMP 表进行一次。

更新:如果 orders_id 的数据类型为 varchar，只需将其转换为 INTEGER，如下所示:

SELECT     s.id 
FROM
(
    SELECT id
    FROM
    (
       SELECT t4.n * 1000 + t3.n * 100 + t2.n * 10 + t1.n + 1 AS id
       FROM         TEMP AS t1
       CROSS JOIN TEMP AS t2
       CROSS JOIN TEMP AS t3
       CROSS JOIN TEMP AS t4
  ) t WHERE id between 1000 AND @maxid
) s 
LEFT JOIN
(
    SELECT CONVERT(orders_id, UNSIGNED INTEGER) AS orders_id 
    FROM orders
) t ON s.id = t.`orders_id` 
WHERE t.`orders_id` IS NULL;

Updated SQL Fiddle Demo