[英]SQL Server : check not existing number into a table
I have a Clients
table already populated by thousands of records and now I need to search for a non-existing number in the card number
column starting from the number x
.我有一个已经由数千条记录填充的Clients
表,现在我需要从数字x
开始在card number
列中搜索一个不存在的数字。
Example: I would like to search for the first available card number
starting from number 2000.示例:我想从号码 2000 开始搜索第一个可用的card number
。
Unfortunately I cannot select MAX()
as there are records with 9999999 (which is the limit).不幸的是,我不能 select MAX()
因为有 9999999 的记录(这是限制)。
Is it possible to do this search through a single SELECT
?是否可以通过单个SELECT
进行此搜索?
If the credit card is represented as integer in your table and your starting number is 2000
you could do something like:如果信用卡在您的表中表示为 integer 并且您的起始编号是2000
,您可以执行以下操作:
SELECT top 1 (card_id + 1)
FROM CreditCards t
WHERE card_id IN (
SELECT card_id
FROM CreditCards
WHERE card_id LIKE '%[2][0][0][0]%'
)
AND NOT EXISTS (SELECT 1 FROM CreditCards t2 WHERE t2.card_id = t.card_id + 1)
ORDER BY card_id
Example data (Table: CreditCards):示例数据(表:信用卡):
card_id card_id |
---|
2000002 2000002 |
2000103 2000103 |
2000000 2000000 |
2000108 2000108 |
20001006 20001006 |
3000201 3000201 |
Result is: 2000001结果是:2000001
Note that %[2][0][0][0]%
is fixed here.注意%[2][0][0][0]%
在这里是固定的。 You could also introduce a parameter.您还可以引入一个参数。
It is not an optimal solution, but it does the work.这不是一个最佳解决方案,但它确实有效。
It's possible with a few nested SELECT
s:可以使用一些嵌套的SELECT
:
SELECT MIN(`card_number`) + 1 as next_available_number
FROM( SELECT (2000-1) as `card_number`
UNION
SELECT `card_number`
FROM clients
WHERE `card_number` >= 2000
) tmp
WHERE NOT EXISTS ( SELECT NULL
FROM clients
WHERE `card_number` = tmp.`card_number` + 1 )
It can be done with a self-join on your clients
table, where you search for the lowest cardnumber
for which the cardnumber + 1
does not exist.这可以通过clients
表上的自联接来完成,您可以在其中搜索不存在cardnumber + 1
的最低cardnumber
。
In case x
is 12
, the query would be:如果x
是12
,则查询将是:
SELECT MIN(cardnumber) + 1
FROM clients
WHERE cardnumber + 1 NOT IN (SELECT cardnumber FROM clients)
AND cardnumber + 1 > 12
Eg.例如。 with a dataset of有一个数据集
INSERT INTO clients (cardnumber) VALUES
(1),(2),(3),(4),(5),(6),(7),(8),(9),(11),(12),(13),(14),(15),(17),(18)
this returns 16, but not 10. Example on SQL Fiddle .这将返回 16,但不是 10。 SQL Fiddle上的示例。
I think this is very similar to this question , but the minimum criteria is new.我认为这与这个问题非常相似,但最低标准是新的。
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