An if statement consists of a Boolean expression followed by do, one or more executable statements and finally an end keyword. Code in if statement executes only if Boolean condition evaluates to true.

An if statement can be followed by an optional else statement(within the do..end block), which executes when the Boolean expression is false.

An unless statement has the same body as an if statement. The code within unless statement executes only when the condition specified is false.

An unless..else statement has the same body as an if..else statement. The code within unless statement executes only when the condition specified is false.

A cond statement is used where we want to execute code on basis of several conditions. It kind of works like an if…else if….else construct in several other programming languages.

Case statement can be considered as a replacement for switch statement in imperative languages. Case takes a variable/literal and applies pattern matching to it with different cases. If any case matches, Elixir executes code associated with that case and exits case statement.