Understanding Oracle aliasing - why isn't an alias not recognized in a query unless wrapped in a second query?

Question

I have a query

SELECT COUNT(*) AS \"CNT\",
       imei
FROM   devices  

which executes just fine. I want to further restrict the query wi

Answer 1

The simple answer is that the AS clause defines what the column will be called in the result, which is a different scope than the query itself.

In your example, using the HAVING clause would work best:

SELECT COUNT(*) AS "CNT",
       imei
FROM   devices
GROUP  BY imei
HAVING COUNT(*) > 1