Question

I have the query below which uses a union to pull data from three tables.

SELECT * FROM (SELECT 

    *,'table1' AS 'tbl', colour AS get_colour(created_date) FROM table1 WHERE customer = '11' UNION SELECT

    *,'table2' AS 'tbl', colour AS get_colour(created_date) FROM table2 WHERE customer = '11' UNION SELECT

    *,'table3' AS 'tbl', colour AS get_colour(created_date) FROM table5 WHERE customer = '11' 

    ORDER BY colour ASC

) as c

I am trying write the function below into SQL so that I can sort my results by colour.

My PHP example function is as follows.

function get_colour($date) {

    $days = floor((time() - strtotime($date))/(60*60*24));

    if(empty($date) || $date == "-") return "grey";

    elseif($days <= 7) return "green";

    elseif($days <= 14) return "orange";

    else return "red";
}

I have looked into using CASE SELECT and IF STATEMENTS but need a little help getting started.

Any help or direction would be appreciated.

Answer 1

I won’t give you an out-of-the-box solution but consider this query:

SELECT
    IF(DATEDIFF(TODAY, YESTERDAY) <= 7, "green",
        IF(DATEDIFF(TODAY, YESTERDAY) <= 14, "orange",
            "red")) as COLOUR
FROM (
    SELECT
    NOW() as TODAY,
    DATE_SUB(NOW(), INTERVAL 15 DAY) as YESTERDAY) T;

It should help you 😉