How to use not operator in SQL using vb.net

Question

My problem now is about how to use "not equal" in SQL. Here is my code:

Dim cmd As New SqlClient.SqlCommand
    With cmd
        .CommandText = "SELECT [Position],[Partylist],[Fullname],[Lvl],[Votes] FROM tbl_cands WHERE [Department] = '" & elem & "'AND [PositionID]=" & pres & ""
        .CommandType = CommandType.Text
        .CommandTimeout = 30
        .Connection = conn
    End With
    Dim dt As New DataTable
    dt.Load(cmd.ExecuteReader)

I need not to display fullname that is not equivalent to None.

This code looks like it could open you to SQL injection hacks. Consider using parameterized techniques instead. — Polynomial, Nov 06 '13 at 07:00
Do you mean just adding `AND [Fullname] <> 'None'` to your query? — Szymon, Nov 06 '13 at 07:09

score 1 · Answer 1 · answered Nov 06 '13 at 07:29

1

All you have to do is to add that to your query:

AND [Fullname] <> 'None'

answered Nov 06 '13 at 07:29

Szymon

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score 1 · Accepted Answer · edited May 23 '17 at 11:45

If you are checking for NULL then the code is:

AND [Fullname] IS NOT NULL

If you want to check the value isn't a zero length string:

AND [Fullname] <> ''

If you want to check it isn't a specific value that denotes no data:

AND [Fullname] <> 'None'

But in any case, I strongly recommend you read the following link and learn how to use parameterization for your SqlCommand object. If you don't escape strings correctly you leave yourself vulnerable to injection hacks:

How to use parameters "@" in an SQL command in VB

How to use not operator in SQL using vb.net

2 Answers2