Explain why the following command would create an error, and what changes could be made to fix the error.
SELECT V_CODE, SUM(P_QOH)
FROM PRODUCT;
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
The provided command "SELECT V_CODE, SUM(P_QOH) FROM PRODUCT;" might cause an error because when using the SUM function in a SELECT statement, you should also include a GROUP BY clause.
To fix the error, you need to modify the command to include the GROUP BY clause, specifying the column(s) you want to group by:
SELECT V_CODE, SUM(P_QOH)
FROM PRODUCT
GROUP BY V_CODE;
This modified command will group the results by the "V_CODE" column and calculate the sum of "P_QOH" for each unique value of "V_CODE".
The given command, `SELECT V_CODE, SUM(P_QOH) FROM PRODUCT;`, would likely result in an error because it is missing a `GROUP BY` clause.
To fix the error and correctly execute the query, you need to specify the column(s) to group the results by. Since you are using the `SUM` aggregate function, you need to group the data by the column(s) that you are not aggregating. In this case, that would be the `V_CODE` column.
The corrected query would look like this:
```
SELECT V_CODE, SUM(P_QOH)
FROM PRODUCT
GROUP BY V_CODE;
```
With this change, the query will correctly group the records by the `V_CODE` column and calculate the sum of the `P_QOH` column for each unique value of `V_CODE`.