SQL Finding Duplicate Values of Rows Where Another Field has a Value

It seems that you want all rows, where the FieldB value is not uniformly NULL.

This gives you the list of FieldAs with that characteristic:

select FieldA
from t
group by FieldA
having count(FieldB) > 0;

If you actually want the rows with the NULL values, then:

select FieldA, FieldB
from (select t.*, count(FieldB) over (partition by FieldA) as cnt
      from t
     ) t
where cnt = 0;

To get all FieldA where one of them is canines:

select distinct FieldA
from t
where FieldB = 'canine';

To get all the rows, use this in a where clause:

select *
from t
where t.FieldA in (select distinct FieldA
                   from t
                   where FieldB = 'canine'
                  );

Your help allowed me to find it.. Thank you all. What i was looking for was:

SELECT FieldA
FROM t
WHERE FieldB = 'Canines'
AND FieldA 
IN
(
    SELECT FieldA
    FROM t
    GROUP BY FieldA
    HAVING COUNT(FieldA) > 1
)

Thank you! Thank you!

To get all rows where count(fielda) > 1 and one of fieldb has the value canine

select t1.fielda
from mytab t1
join (select fielda, count(*) as dups
      from mytab
      group by fielda) t2 on t2.fielda = t1.fielda
where t1.fieldb = 'canine'
and t2.dups > 1

SQLFiddle

If you want every row where there are duplicates, and where at least one item in Field B is not null, this will pull that:

SELECT *
FROM Table
WHERE FieldA IN (SELECT DISTINCT FieldA
                 FROM Table
                 WHERE FieldB IS NOT NULL)
   AND FieldA IN (SELECT FieldA
                 FROM Table
                 GROUP BY FieldA
                 HAVING COUNT(*)>1)