putting trim statement in LINQ

Question

I have the employee numbers in the database starting stored this way

EmployeeNumber
E123456
E999999
E666666
E111111

I want to write a LINQ statement to match the database EmployeeNumber with employeeId that is passed from web. I wrote the LINQ like this:

 _akContext.EmployeeInfos.Where(e => e.EmployeeNumber.TrimStart('E') == employeeId).OrderBy(e => e.EmployeeInfoId).Select(e => e.EmployeeInfoId).ToList();

With the above LINQ statement, I keep getting an error saying:

The LINQ expression 'DbSet<EmployeeInfo>()

.Where(e => e.EmployeeNumber.TrimStart(E) == __TrimStart_0)' could not be translated
```below is the screenshot:

![User's image](/api/attachments/a76a029e-307c-4571-8af8-12fac6863195?platform=QnA)

how can I compare both employeeId and EmployeeNumber in LINQ

Answer 1

Thanks for posting your question in the Microsoft Q&A forum.

The TrimStart method is not supported in LINQ to SQL because it cannot be translated to SQL.

You can achieve the same result by using the SqlFunctions class, specifically the SqlFunctions.PatIndex method, which simulates the functionality of TrimStart in LINQ to SQL.

_akContext.EmployeeInfos.Where(e => e.EmployeeNumber.Substring(SqlFunctions.PatIndex("%[^E]%", e.EmployeeNumber) - 1) == employeeId)
    .OrderBy(e => e.EmployeeInfoId)
    .Select(e => e.EmployeeInfoId)
    .ToList();

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