How to add null values into database

Question

I am trying to add some data into my database. I have 5 columns which all allow null values and all have datatype of varchar. But in my program I am passing only 4 values and fifth column should be empty. When I do this shows error

Number of supplied values does not match in the number of databse columns

How can I add NULL values into database?

My button click

protected void Button1_Click(object sender, EventArgs e)
{
    try
    {
        string str=mas.empdetedit(ddid.SelectedItem.Text,txtname.Text,txtcon.text,txtval.text);
    }

My class is

public string empdetedit(string id, string name, string con, string val)
{
    string str=insert into table values('"+id+"','"+name+"','"+con+"','"+val+"'");
    conn.nonquery(str);
}

Soner Gönül, How you edited my question like this??I cant type question like this format — Signet softwaretrainee
– Signet softwaretrainee, Commented Sep 26, 2014 at 10:57
possible duplicate of How to insert null value in Database through parameterized query — emerson.marini
– emerson.marini, Commented Sep 26, 2014 at 10:59
Please take a tutorial with database record manipulation. Now you asking questions step after step: how insert null, date, boolean... — Renatas M.
– Renatas M., Commented Sep 26, 2014 at 11:01

Keith · Accepted Answer · 2014-09-26 11:01:17Z

2

The syntax to insert into only specific columns of a table is:

INSERT INTO table_name (column1,column2,column3) VALUES (value1,value2,value3)

You are not explicitly specifying the column names, so the database thinks you are giving values for all of them.

answered Sep 26, 2014 at 11:01

Keith

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1 Comment

marc_s Over a year ago

And also: use a parametrized query to do the insert to avoid SQL injection attacks!

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