I have a weird problem with the optimization and I cannot find what is causing this.

I have a SQL command that is having several INNER JOINs. So, the command is like this:

SELECT Member.Numero,Status.Name FROM Member;
 INNER JOIN Status ON Member.NoStatus=Status.Numero;
 WHERE Member.NumeroI=4112;
 ORDER BY 1 ASC

The SQL command has been simplified for the example.

If I use the command as is, the result is not optimized. I could take like 1 to 3 seconds to obtain the result. I can see sometime the progress bar showing the progress or if under a second, I can see something like 0.94, 0.92, etc.

But, if I change one field in the SQL, like this:

SELECT Member.Numero,Status.Numero FROM Member;
 INNER JOIN Status ON Member.NoStatus=Status.Numero;
 WHERE Member.NumeroI=4112;
 ORDER BY 1 ASC

The result is fully optimized. I get the result in 0.00 second.

So, why changing the field from Status.Name to Status.Numero would cause such a reaction?