Examine the following code:
Which statement is true about the execution of the above code?
A. It executes and displays null.
B. It executes and the condition returns true.
C. It executes and control goes to the else statement.
D. It fails because no value is assigned to the v_myage variable.
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I also think correct answer is C.
Below quotes and test code confirms it.
https://docs.oracle.com/cd/B19306_01/server.102/b14200/sql_elements005.htm
“To test for nulls, use only the comparison conditions IS NULL and IS NOT NULL. If you use any other condition with nulls and the result depends on the value of the null, then the result is UNKNOWN.”
“A condition that evaluates to UNKNOWN acts almost like FALSE. For example, a SELECT statement with a condition in the WHERE clause that evaluates to UNKNOWN returns no rows. However, a condition evaluating to UNKNOWN differs from FALSE in that further operations on an UNKNOWN condition evaluation will evaluate to UNKNOWN. Thus, NOT FALSE evaluates to TRUE, but NOT UNKNOWN evaluates to UNKNOWN.”
set serveroutput on;
declare
v_myage number;
begin
if v_myage<11 then
dbms_output.put_line(' I am a child ');
else
dbms_output.put_line(' I am not a child ');
end if;
end;
/
I am not a child