selecting a column greater than a specified value

Question

This is my current code:

select distinct categoryid, min(weight), max(weight), round(avg(weight), 2) as AVG_WEIGHT
from inventorypart
where categoryid is not null
group by categoryid;

I need to select the categoryid that has the avg weight greater than 4.

i have tried the following with no sucess

where categoryid is not null and avg(weight) > 4

Answer 1

The WHERE keyword cannot be used with aggregate functions, as WHERE is applied before GROUP BY. Use HAVING instead:

SELECT DISTINCT categoryid, MIN(weight), MAX(weight), ROUND(AVG(weight), 2) AS AVG_WEIGHT
FROM inventorypart
WHERE categoryid IS NOT NULL
GROUP BY categoryid
HAVING AVG(weight) > 4