Question

I have 4 records in my SQL table that and I’m doing a SQL select statement to select records based on a certain criteria but I’m not picking any records up. Can someone please help?

Here is my SELECT statement:

string Sql = "";  
Sql = @"SELECT * FROM " + _dtlName + " 
        WHERE Shipper_No = '" + sidNo + "' 
        AND Job_Code != '" + "R" + "'";  

I have 3 records that have a Null for Job_Code and 1 record that has an R.

Based on that, I should pickup the 3 records with the NULL Job_Code but it returns 0 records.

Answer 1

I suspect the problem is that a comparison between any non-null value and a null value doesn’t return a value of true or false, but null. So your query should probably be:

string sql = "SELECT * FROM " + _dtlName + " WHERE Shipper_No = @ShipperNo " +
             "AND (Job_Code IS NULL OR Job_Code != 'R')";

(Note that I’ve extracted a parameter for Shipper_No – you shouldn’t be including values directly in your SQL like that. Obviously you’ll need to then set the parameter value in the SQL command.)

Also note that <> is more common in SQL to represent “not equal to”, but I believe T-SQL allows either form.