Hi, all
If I have two columns, zip_cd and zip_4_cd, and I want to check for any records with identical zip_cd and zip_4_cd, how would I do that? I've tried different ways but I still can't figure it out...
Some attempts:

SELECT sum(COUNT(DISTINCT ZIP_CD))
FROM table name
group by zip_4_CD

select count(zip_4_cd))
from table_name
where zip_cd=
(select min(zip_cd)
from table_name
group by zip_cd)

SELECT
COUNT(ZIP_CD + ZIP_4_CD) AS Expr1,
ZIP_CD + ZIP_4_CD AS Expr2
FROM table name
GROUP BY ZIP_CD + ZIP_4_CD

but zip_cd and zip_4_cd are two different columns.