Re: string not equal query, postgresql 9.4.4

John Scalia <jayknowsunix@xxxxxxxxx> · Thu, 17 Sep 2015 19:52:57 -0500



    On 9/17/2015 6:49 PM, David G. Johnston wrote:

    
        On Thu, Sep 17, 2015 at
            6:18 PM, John Scalia <jayknowsunix@xxxxxxxxx> wrote:

        
              SELECT * FROM results where result <> 'PASS';

              
              and it produced all the rows, not just the ones beginning
              with visc60 that I expected. Based on what you had
              written, I should have seen the correct output. So, any
              ideas?

            
                EXPLAIN ANALYZE SELECT * FROM results WHERE result
                <> 'PASS';
            
            
              What
                happens when you run the following?  Do you see the same
                incorrect behavior?
            
            
                WITH
                  vals (v) AS (

                
                VALUES
                  ('PASS'::char(4)), ('FAIL'::char(4))
                )
                SELECT 
                  
                    DISTINCT 
                  *
                FROM
                  vals
                WHERE
                  v <> 'PASS'::char(4);
                

              David
                J.
               
          
    I tried your code above, and some additional queries prior to your
    message arriving, and I see now why I'm still getting multiple row
    beyond my original expecting. Carefully looking at the rows being
    produced showed that each instrument is performing a powerup test
    and all those passed. I guess I was just expecting too much from
    distinct and I understand why. I just need to add a second where
    clause if I can figure out how to make the powerup test clearly
    indicated as such in the table.

    
    Thanks for everyone's help, I should have examined the automated
    data collection more closely.

    --

    Jay