SQL not a single group group function error

Question

I am having a hard time getting my oracle developer query to output correctly. When I have the avg function in it, it gives me not a single group group error. When I take it

Answer 1

When you include an aggregate function (like avg, sum) in your query, you must group by all columns you aren't aggregating.

SELECT LGBRAND.BRAND_ID, LGBRAND.BRAND_NAME, AVG(LGPRODUCT.PROD_PRICE)AS AVGER
FROM LGPRODUCT, LGBRAND
WHERE LGPRODUCT.BRAND_ID = LGBRAND.BRAND_ID
GROUP BY
LGBRAND.BRAND_ID,
LGBRAND.BRAND_NAME
ORDER BY BRAND_NAME

Answer 2

You are using an AGGREGATION function and in order to do so you have to group all the data that would have to be aggregated.

SELECT LGBRAND.BRAND_ID, LGBRAND.BRAND_NAME, AVG(LGPRODUCT.PROD_PRICE) AS AVGER
  FROM LGPRODUCT, LGBRAND
 WHERE LGPRODUCT.BRAND_ID = LGBRAND.BRAND_ID
group by LGBRAND.BRAND_ID, LGBRAND.BRAND_NAME -- This line here
ORDER BY BRAND_NAME;

Answer 3

For your newly added fields, you didn't used group by, hence you are getting this error, so by including that newly added fields to group by you will resolve this error and group all the data that would have to be aggregated.

Answer 4

SELECT LGBRAND.BRAND_ID, LGBRAND.BRAND_NAME, AVG(LGPRODUCT.PROD_PRICE)AS AVGER
FROM LGPRODUCT, LGBRAND
WHERE LGPRODUCT.BRAND_ID = LGBRAND.BRAND_ID
GROUP BY LGBRAND.BRAND_ID, LGBRAND.BRAND_NAME
ORDER BY BRAND_NAME;

OR

SELECT LGBRAND.BRAND_ID, LGBRAND.BRAND_NAME, AVG(LGPRODUCT.PROD_PRICE)AS AVGER
FROM LGPRODUCT INNER JOIN LGBRAND
ON LGPRODUCT.BRAND_ID = LGBRAND.BRAND_ID
GROUP BY LGBRAND.BRAND_ID, LGBRAND.BRAND_NAME
ORDER BY BRAND_NAME;

Note
Whenever an aggregate function(SUM, COUNT, AVG, MIN, MAX, ..) is used in SELECT all the other column in that SELECT that are not contained in any aggregate function must come in GROUP BY clause