msql 中的 IF 函数

Question

What I need- A column that displays an X for each digit of the card_number column except for the last four digits.

what I need- If the card number contains 16 digits, it should be displayed in this format: XXXX-XXXX-XXXX-1234, where 1234 are the actual last four digits of the number.

If the card number contains 15 digits, it should be displayed in this format: XXXX-XXXXXX-X1234. (Hint: Use an IF function to determine which format to use.)

Below is what I got, I need the if function to do the above:

SELECT card_number, 
       length(card_number) as card_number_length,
       right(card_number, 4) AS last_four_digits,
       CONCAT('xxxx-xxxx-xxxx-', + RIGHT (card_number,4)) AS formatted_number
FROM Orders;

Answer 1

Rather simple, use the IF function inside the CONCAT :

SELECT card_number, 
       length(card_number) as card_number_length,
       right(card_number, 4) AS last_four_digits,
       CONCAT(IF(length(card_number)=15, 'XXXX-XXXXXX-X', 'XXXX-XXXX-XXXX-'), RIGHT (card_number,4)) AS formatted_number
FROM Orders;