Query Table compare for field values NOT Existing in a specific table 1

[ljsmith91]

I have a database with 3 different tables. Each has a field(model) that is used for the exact same purpose. In simple terms, I want to eliminate the field in 2 of the tables so that the field is contained in only 1 table instead of 3. In order to do this, I want to know how many distinct records of this field exist in each table. If Table1 is the table that I want to keep the field, how do I create a query that will list the similar field in both Table2 and Table3 only if it doesn't already have a record in Table1? Is there a way to query and get a compare of field values from Table2 and Table3 that DO NOT exist in Table1? I know it's some sort of OUTER Join logic but I can't seem to find a query that simplifies this. This one sample that just doesn't do the trick for me.

SELECT t1_model,t2_model,t3_model
from T1
Outer Join T2
on t1_model <> t2_model
Outer join t3
on t1_model <> t3_model

Thanks for any quidance. -ls

 

[PWise]

Select model
from(Select model
from t2
union
Select model
from t3
)T1And2
left join ti
on t1.model=T1And2.model
where t1.model is null

will give models that are in t2 and t3 that are not in t1