IF-ELSIF-ELSE control flow in PostgreSQL - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of IF-ELSIF-ELSE control flow in PostgreSQL?

It allows you to execute different blocks of code based on conditions, choosing which code to run depending on whether conditions are true or false.

beginner

Write the basic syntax of IF-ELSIF-ELSE in a PostgreSQL PL/pgSQL block.

IF condition1 THEN<br>   -- statements<br>ELSIF condition2 THEN<br>   -- statements<br>ELSE<br>   -- statements<br>END IF;

beginner

Can you have multiple ELSIF branches in an IF statement in PostgreSQL?

Yes, you can have as many ELSIF branches as needed to check multiple conditions in sequence.

intermediate

What happens if none of the IF or ELSIF conditions are true and there is no ELSE branch?

No code inside the IF block runs, and the program continues after the END IF statement.

intermediate

How does IF-ELSIF-ELSE differ from CASE statements in PostgreSQL?

IF-ELSIF-ELSE is used for conditional branching with boolean expressions, while CASE is used for comparing an expression against multiple values. IF-ELSIF-ELSE can handle complex conditions more flexibly.

Which keyword starts an IF-ELSIF-ELSE control flow block in PostgreSQL?

A BEGIN

B IF

C CASE

D LOOP

The IF keyword starts the conditional control flow block.

What keyword is used to check an additional condition after IF in PostgreSQL?

A ELSIF

B ENDIF

C WHEN

D ELSE

ELSIF is used to check another condition if the previous IF or ELSIF was false.

What keyword ends an IF-ELSIF-ELSE block in PostgreSQL?

A END

B FINISH

C END IF

D STOP

END IF marks the end of the IF-ELSIF-ELSE control flow block.

If none of the IF or ELSIF conditions are true, which block runs?

A ELSE block

B ELSIF block

C IF block

D No block runs

The ELSE block runs if all IF and ELSIF conditions are false.

Can you omit the ELSE branch in an IF-ELSIF-ELSE statement?

A Only in PostgreSQL 14+

B No, it is mandatory

C Only if there is one ELSIF

D Yes, it is optional

The ELSE branch is optional; if omitted and no conditions match, no code runs.

Explain how IF-ELSIF-ELSE control flow works in PostgreSQL and give a simple example.

Think about checking conditions one by one and running code for the first true condition.

Describe the difference between IF-ELSIF-ELSE and CASE statements in PostgreSQL.

Consider when you want to check complex conditions versus matching values.