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Null Value RRS feed

  • Question

  • User-1499457942 posted

    Hi

      I have below code and value in m_location is Null but it is still going in the below condition

    if (!string.IsNullOrEmpty(m_Location))
    {
    strQuery = strQuery + " " + m_Location;
    }

    In Database when i run below command it shows no record but in field it shows Null

    select * FROM [test].[dbo].[Data] where Location is null

    Thanks

    Thursday, September 20, 2018 4:16 PM

Answers

  • User753101303 posted

    And your db is ? Once again the behavior you describe is exactly what you have if storing a 4 characters 'NULL' string rather than really a NULL value.

    Try SELECT LEN(field) FROM YourTable WHERE Field='NULL' -- Or maybe LENGTH depending on your db

    If it shows 4 rather than NULL you definitively stored a 'NULL' string in your db.

    • Marked as answer by Anonymous Thursday, October 7, 2021 12:00 AM
    Thursday, September 20, 2018 5:33 PM

All replies

  • User753101303 posted

    Hi,

    This is what happens if m_Location or your db column is not null. Are you 100% sure you don't have a 4 character "null" string or may be whitespaces rather than really a string which is null ???

    Try to show m_Location.Length. If it shows a value rather than throwing a NullReferenceException you do have a non null string.

    Thursday, September 20, 2018 5:17 PM
  • User-1499457942 posted

    Hi

        It shows NULL in field . When i run select statement for is null records it shows nothing. When i write select statement as field= 'NULL' then it shows records

    Thanks

    Thursday, September 20, 2018 5:25 PM
  • User753101303 posted

    And your db is ? Once again the behavior you describe is exactly what you have if storing a 4 characters 'NULL' string rather than really a NULL value.

    Try SELECT LEN(field) FROM YourTable WHERE Field='NULL' -- Or maybe LENGTH depending on your db

    If it shows 4 rather than NULL you definitively stored a 'NULL' string in your db.

    • Marked as answer by Anonymous Thursday, October 7, 2021 12:00 AM
    Thursday, September 20, 2018 5:33 PM