VB 2010 OleDbCommand with parameter that me be null

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Hello.

I have this code:

Dim conz As New OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\Bdados\CV_PARTS.accdb;Persist Security Info=False")
Dim cmd As New OleDbCommand("SELECT * FROM PECAS_IN WHERE Fornecedor = ?)", conz)

After this I create a parameter and assign it to the text of a combobox. Supposing I want to retrieve all data by leaving the combobox empty what code should I use? I tried:

Dim cmd As New OleDbCommand("SELECT * FROM PECAS_IN WHERE (Fornecedor = ? OR Fornecedor Like "*")

But it does not work. What is the correct syntax?

Thank you.
Octavio

Posted 24-Jun-11 6:18am

Member 8014117

Updated 24-Jun-11 6:23am

Kschuler

v2

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Prerak Patel · Answer 1 · 2011-06-24T06:31:00

Solution 1

First of all, you can't use double quote like this in VB.

Try

Dim cmd As New OleDbCommand("SELECT * FROM PECAS_IN WHERE (Fornecedor = ? OR Fornecedor Like ""*""")

Posted 24-Jun-11 6:31am

Prerak Patel

Member 8014117 · Answer 2 · 2011-06-24T06:40:00

Solution 2

Hello.

I tried your solution but it still does not work...

Octavio

Posted 24-Jun-11 6:40am

Member 8014117

Member 8014117 · Answer 3 · 2011-06-24T06:54:00

Solution 3

Hi.

I found out!

Dim cmd As New OleDbCommand("SELECT * FROM PECAS_IN WHERE Fornecedor LIKE '%' + ? + '%'"

It's a bit weird but it does work. Nothing like using SQL on Oracle, which is what i'm used to.

Posted 24-Jun-11 6:54am

Member 8014117