Question

I have in my column (id) values  
                               4
                               5
                               10

我想选择不存在的最小nubmer。示例值1然后是2然后是3然后是6 .....

我正在尝试此代码

IF not EXISTS(SELECT min(id) from table1) select...

Answer 1

您可以找到不存在Id + 1行的第一行。

试试这个。

SELECT TOP 1 t1.Id+1 as ID
 FROM table t1
 WHERE NOT EXISTS(SELECT * FROM table t2 WHERE t2.Id = t1.Id + 1)
ORDER BY t1.Id;

检查一下.. Online Demo HERE

Answer 2

在您的数据库中

Create a numbers table，这很容易：

SELECT MIN(Numbers.n) As MinMissingId
FROM [Numbers] 
WHERE NOT EXISTS
(
    SELECT 1 FROM dbo.TableName t WHERE Numbers.n = t.ID
)

这是一个小脚本，用于创建从Aaron文章中复制的表格：

SELECT TOP (1000000) n = CONVERT(INT, ROW_NUMBER() OVER (ORDER BY s1.[object_id]))
INTO dbo.Numbers
FROM sys.all_objects AS s1 CROSS JOIN sys.all_objects AS s2
OPTION (MAXDOP 1);

CREATE UNIQUE CLUSTERED INDEX n ON dbo.Numbers(n)
-- WITH (DATA_COMPRESSION = PAGE)
;

从不存在的列中选择最小数量

2 个答案: