Which SQL statement returns a numeric value?
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SELECT ADD_MONTHS(MAX(hire_Date), 6) FROM EMP;
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SELECT ROUND(hire_date)FROM EMP;
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SELECT sysdate-hire_date FROM EMP;
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SELECT TO_NUMBER(hire_date + 7)FROM EMP;
In Oracle SQL, subtracting two dates returns a numeric value representing the number of days between them. The sysdate-hire_date expression performs date arithmetic and yields a number. ADD_MONTHS returns a date, ROUND applied to a date returns a date, and TO_NUMBER cannot directly convert a date expression.
To answer this question, let's go through each option to understand why it is correct or incorrect:
Option A) SELECT ADD_MONTHS(MAX(hire_Date), 6) FROM EMP; This option calculates the maximum hire date from the EMP table and adds 6 months to it using the ADD_MONTHS function. The result is a date value, not a numeric value.
Option B) SELECT ROUND(hire_date) FROM EMP; This option rounds the hire_date column values to the nearest whole number. The result is a date value, not a numeric value.
Option C) SELECT sysdate-hire_date FROM EMP; This option subtracts the hire_date column values from the current date (sysdate) using the minus operator. The result of this subtraction operation is a numeric value representing the number of days between the hire date and the current date.
Option D) SELECT TO_NUMBER(hire_date + 7) FROM EMP; This option adds 7 days to the hire_date column values and then converts the result to a numeric value using the TO_NUMBER function. The result is a numeric value.
The correct answer is option C. This option returns a numeric value because it calculates the number of days between the hire date and the current date.