Review Questions

1.	What is another way to write the following SQL statement by using another function? select empno || lpad(initcap(ename), 40-length(empno),’.’) "Employee Directory" from emp;
2.	Which function would you use to perform an explicit conversion from a number to a string?
3.	How can you rewrite the function call NUMTOYMINTERVAL(17,’year’) using the function TOYMINTERVAL?
4.	What is the result of a number added to a NULL value?
5.	What is the result of formatting the number -232.6 using the format mask ‘9999.99S’?
6.	Rank the following operators or conditionals based on priority, from highest to lowest: *, OR, ||, >=
7.	The DUAL table has how many rows and how many columns?
8.	True or false: Strings and numbers can be concatenated.
9.	Write a SELECT statement with a built-in function or functions that will format the string ‘Queen’ with the ‘!’ character padded for a total of 20 characters on the left side, and with the ‘?’ character padded for a total of 30 characters on the right. (Hint: Use nested functions.)
10.	What functionality does the new Oracle TIMESTAMP datatype have over the DATE datatype?

Answers

1.	You can rewrite the statement using the CONCAT function: select concat(empno, lpad(initcap(ename), 40-length(empno),’.’) "Employee Directory" from emp;
2.	You can use the TOCHAR function to convert a number to a string.
3.	You can rewrite the function call as TOYMINTERVAL(‘17-00’).
4.	The result of a number added to a NULL is NULL.
5.	The resulting format is 232.60-.
6.	*, ||, >=, OR
7.	The DUAL table has one row and one column. The column is named DUMMY and has a value of ‘X’.
8.	True, before the number is concatenated with the string, it is implicitly converted to a string.
9.	select rpad(lpad(‘Queen’,20,’!’),30,’?’) from dual; RPAD(LPAD(‘QUEEN’,20,’!’),30,’ ------------------------------ !!!!!!!!!!!!!!!Queen??????????
10.	The TIMESTAMP datatype stores the time in seconds to up to nine digits of precision.