openquery giving different results

Question

I have 2 similar queries

select * 
from openquery(powerschool, 
                'select * 
                 from TEACHERS 
                 where teachernumber is not null 
                   and schoolid=''1050'' 
                   and teacherloginid is not null  
                 order by teachernumber') 

and

SELECT * 
from openquery(powerschool, 
              'SELECT NVL(teachernumber,'''') 
               from TEACHERS 
               where teachernumber is not null 
                 and schoolid=''1050'' 
                 and teacherloginid is not null 
               order by teachernumber') 

The first one is giving me 182 rows while the second one gives me 83.

What's wrong with the queries?

Answer 1

Second query never would return a null for the teachers table because of the NVL() so it could return more records depending on the data.

basically the " and teacherloginid is not null " never gets hit because you replace the nulls with ""

Answer 2

Just thoughts...

• Same server? That is, linked server is different in target or credentialss o you are reading a different "TEACHERS" table

• What does running both linked SQL statement actually on the linked server (not locally) give you?