This set of PL/SQL Multiple Choice Questions & Answers (MCQs) focuses on “PL/SQL Conditions”.
1. Which of the following part of the IF-THEN statement gets executed if the condition is false or NULL?
a) IF
b) THEN
c) ELSE
d) IF statement does nothing
View Answer
Explanation: In IF-THEN statement, if the given condition evaluates to true, then the block of code inside the if statement will be executed. If the expression evaluates to false, then the first set of code after the end of the if statement (IF statement does nothing) will be executed.
2. Consider the PL/SQL code below and select the appropriate output –
DECLARE n NUMBER(3) := 100; BEGIN n:= 100; IF( n<50 ) THEN dbms_output.put_line('n is less than 50 ' ); END IF; dbms_output.put_line('value of n is : ' || n); END; /
a)
n IS less than 50
b)
n IS less than 50 VALUE OF n IS : 100 PL/SQL PROCEDURE successfully completed.
c)
VALUE OF n IS : 100 PL/SQL PROCEDURE successfully completed.
d)
n IS less than 50 VALUE OF n IS : 100
Explanation: The output of the given PL/SQL code will be –
VALUE OF n IS : 100
PL/SQL procedure successfully completed.
Since, the given condition is false so, the IF-THEN statement will be not executed.
3. Which of the following part of the IF-THEN-ELSE statement gets executed if the condition is false or NULL?
a) IF
b) THEN
c) ELSE
d) END IF
View Answer
Explanation: In IF-THEN-ELSE statement, if the given condition evaluates to true, then the block of code inside the if statement will be executed. If the expression evaluates to false, then the block of code inside the else statement will be executed.
4. Consider the PL/SQL code below and select the appropriate output.
DECLARE n NUMBER(3) := 100; BEGIN n:= 100; IF( n < 50 ) THEN dbms_output.put_line('n is less than 50 ' ); ELSE dbms.output.put_line(‘n IS greater than 50’); END IF; dbms_output.put_line('value of n is : ' || n); END; /
a)
n IS less than 50 n IS greater than 50
b)
n IS greater than 50 VALUE OF n IS : 100 PL/SQL PROCEDURE successfully completed.
c)
VALUE OF n IS : 100 PL/SQL PROCEDURE successfully completed.
d)
n IS less than 50 VALUE OF n IS : 100
Explanation: The output of the given PL/SQL code will be –
n IS greater than 50 VALUE OF n IS : 100
PL/SQL procedure successfully completed.
Since, the given condition is false so, the ELSE statement will be executed.
5. How many ELSIF’s can an IF-THEN-ELSIF statement contain in PL/SQL?
a) 1
b) 5
c) 100
d) No specified limit
View Answer
Explanation: An IF-THEN-ELSIF statement can have zero to many numbers of ELSIF’s but they must come before the ELSE part.
6. Consider the PL/SQL code below and select the appropriate output.
DECLARE n NUMBER(2) := 40; BEGIN IF( n = 10 ) THEN dbms_output.put_line('Value of n is 10 ' ); ELSE IF ( n = 20 ) THEN dbms_output.put_line('Value of n is 20' ); ELSE IF ( n = 30 ) THEN dbms_output.put_line('Value of n is 30' ); ELSE IF ( n = 40 ) THEN dbms_output.put_line('Value of n is 40' ); ELSE dbms.output.put_line(‘VALUE OF n NOT known’); END IF; dbms_output.put_line('value of n is : ' || n); END; /
a)
VALUE OF n IS 40 VALUE OF n IS : 40 PL/SQL PROCEDURE successfully completed.
b)
VALUE OF n NOT known VALUE OF n IS : 40 PL/SQL PROCEDURE successfully completed.
c)
VALUE OF n IS 10 PL/SQL PROCEDURE successfully completed.
d)
VALUE OF n IS 40 VALUE OF n IS : 40
Explanation: The output of the given PL/SQL code will be –
VALUE OF n IS 40 VALUE OF n IS : 40
PL/SQL procedure successfully completed.
Since, the given condition is matched by the last ELSIF so, the corresponding ELSIF statement will be executed. Also, the statement after the END IF will be executed.
7. What is the expression called which is used by the CASE statement to select one statement to execute from the given statements.
a) Boolean Expression
b) Selector
c) Condition
d) Relation
View Answer
Explanation: The CASE statement uses a selector rather than multiple Boolean expressions. A selector is an expression, the value of which is used to select one of several alternatives.
8. Which of the following is the correct syntax for the CASE statement?
a)
CASE selector IF 'value1' THEN Statement1; IF 'value2' THEN Statement2; IF 'value3' THEN Statement3; ... ELSE Statementn; END CASE;
b)
CASE selector WHEN 'value1' Statement1; WHEN 'value2' Statement2; WHEN 'value3' Statement3; ... ELSE Statementn; END CASE;
c)
CASE selector WHEN 'value1' THEN Statement1; WHEN 'value2' THEN Statement2; WHEN 'value3' THEN Statement3; ... ELSE Statementn; END CASE;
d)
CASE selector 'value1' THEN Statement1; 'value2' THEN Statement2; 'value3' THEN Statement3; ... ELSE Statementn; END CASE;
Explanation: The correct syntax for the CASE statement is-
CASE selector WHEN 'value1' THEN Statement1; WHEN 'value2' THEN Statement2; WHEN 'value3' THEN Statement3; ... ELSE Statementn; END CASE;
The WHEN and THEN keywords are used with the CASE statement.
9. What is the CASE statement called when it has no selector and the WHEN clause of the statement contain search conditions.
a) Un-CASE statement
b) Conditional CASE statement
c) Unsearched CASE statement
d) Searched CASE statement
View Answer
Explanation: The Searched CASE statement has no selector and the WHEN clauses of the statement contain search conditions that give Boolean values which helps the statement to decide which of the given statement is to be printed.
10. We can use nested IF-ELSE statements in PL/SQL.
a) True
b) False
View Answer
Explanation: Nested IF-ELSE statements can be used in PL/SQL. Nested IF-ELSE statement means using one IF or ELSE IF statement inside another IF or ELSE IF statement/statements.
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