CASE statement
Next, let’s move on to CASE statements.
The CASE statement is very similar to the IF statement and can often be used interchangeably. In most cases, choosing between IF and CASE is a matter of personal preference.
The syntax is:
CASE case_variable
WHEN value_1 THEN do task A;
WHEN value_2 THEN do task B;
...
ELSE do task Z;
END CASE;
Or
CASE
WHEN condition 1 is met THEN do task A;
WHEN condition 2 is met THEN do task B;
...
ELSE do task Z;
END CASE;
The first syntax allows you to match the value of a variable against a set of distinct values. The second syntax allows you to perform more complex matches such as matching using ranges.
Let’s look at some examples.
Example 1
DELIMITER $$
CREATE FUNCTION case_demo_A(x INT) RETURNS VARCHAR(255) DETERMINISTIC
BEGIN
CASE x
WHEN 1 THEN RETURN 'x is 1';
&...
