Explain why the following command would create an error, and what changes could be made to fix the error.

Question

SELECT V_CODE, SUM(P_QOH)
FROM PRODUCT;

Answer 1

You are missing the Group by:
See the explanation from the Book
The GROUP BY clause is valid only when used in conjunction with one of the SQL aggregate functions, such as
COUNT, MIN, MAX, AVG, and SUM. For example, as shown in the first command set in Figure 7.26, if you try to
group the output by using:
SELECT V_CODE, P_CODE, P_DESCRIPT, P_PRICE
FROM PRODUCT
GROUP BY V_CODE;
you generate a “not a GROUP BY expression” error. However, if you write the preceding SQL command sequence
in conjunction with some aggregate function, the GROUP BY clause works properly. The second SQL command
sequence in Figure 7.26 properly answers the question

Answer 2

Walter coming in just a month shy of 4 years after the question was asked. And they said millenials can't focus!