How to generate 6-digit unique numbers in C# or SQL Server?

Question

I want to generate 6-digit unique random numbers for my Users table. This unique code is different from table primary key. It should not be sequential and must be in 6-digit format. I have to ignore numbers like 111111, 222222, ...

I can use the Random() class in C# to generate it but the uniqueness is the key.

Is there any solution to do it in C# (or in SQL Server)?

One way to generate unique 'random' numbers is to encrypt unique inputs: 0, 1, 2, 3, 4, ... Unique inputs will generate unique outputs. — rossum, Nov 19 '16 at 11:21

score 3 · Accepted Answer · edited Aug 31 '17 at 04:42

3

You can try this

    private static string GenerateNewRandom()
    {
        Random generator = new Random();
        String r = generator.Next(0, 1000000).ToString("D6");
        if (r.Distinct().Count() == 1)
        {
            r = GenerateNewRandom();
        }
        return r;
    }

edited Aug 31 '17 at 04:42

daveywc

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answered Nov 19 '16 at 05:51

MMM

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Good solution @Mdhun, thanks. – Nasseh Nov 19 '16 at 05:58
1

it should be `r =GeneratenewRandom();` isn't it? – Damith Nov 19 '16 at 06:18

How to generate 6-digit unique numbers in C# or SQL Server?

1 Answers1