How to insert null in datetime type column in sql server

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醉酒成梦
醉酒成梦 2021-02-20 15:23

I have a table in which there are some datetime type columns. I use a stored procedure to insert values into the table. In the stored procedure I have variables that accept null

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  • 2021-02-20 16:01

    You should just be able to supply null directly as a parameter value:

    if (String.IsNullOrWhitespace(InsertDate.Text)) {
        cmd1.Parameters["@InsertDate"].Value = null;
    } else {
        cmd1.Parameters["@InsertDate"].Value = InsertDate.Text;
    }
    

    Also switched to using String.IsNullOrWhitespace() to check for an empty string.

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  • 2021-02-20 16:04

    You can use this. There i no shortcut!!

    if (InsertDate.Text == "") cmd.Parameters.AddWithValue("@enddate", DBNull.Value); else cmd.Parameters.AddWithValue("@enddate", Convert.ToDateTime(InsertDate.Text));

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  • 2021-02-20 16:05

    To pass null value to db you can use DBNull.Value. Please try this

     if (string.IsNullOrWhiteSpace(InsertDate.Text))
      {
       cmd1.Parameters["@InsertDate"].Value =DBNull.Value;
      }
     else
      {
       cmd1.Parameters["@InsertDate"].Value = InsertDate.Text;
      }
    
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  • 2021-02-20 16:06
    cmd1.Parameters["@InsertDate"].Value = getDate ?? DBNull.Value;
    

    The key being DBNull.Value. I imagine you have a nullable DateTime variable, i.e. DateTime? someVariable. You can test it for null and if it is use DBNull.Value (as shown above).

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  • 2021-02-20 16:06

    try using this

    System.Data.SqlTypes.SqlDateTime.Null
    
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  • 2021-02-20 16:07

    First of all, to be able to insert null into a database column, the column must accept nulls. Open the table in the designer, and see if the relevant column is nullable or not. If it's not and you try to insert a null value, you'll get the error:

    Cannot insert the value NULL into column 'InsertDate', table 'TableName'; column does not allow nulls.

    That said, since you are using stored procedures to insert data, I would recommend using default values for the parameters on the procedure level, instead of burdening the aplication code. Than, you can just not set the parameter on the application side, and it would work correctly:

     create procedure InsertIntoTable
       -- ....other parameters here...
       @InsertDate datetime = null -- this means that if the value is not supplied, 
                                   -- null is used by default
     as begin
       insert into TableName (InsertDate) values (@InsertDate)
     end
    

    and on the C# side, just do:

    if (!string.IsNullOrWhitespace(InsertDate.Text)) {
      // check to see if the entered text is actually a date
      DateTime insertDate = ... some parsing/verification code...;
      cmd1.Parameters["@InsertDate"].Value = insertDate;
    }
    

    Note that there is no else branch, so if the InsertDate is empty, the parameter is not sent at all.

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