Question

Just getting into SQL stored queries right now… anyway, here’s my database schema (simplified for YOUR convenience):

member
------
id INT PK

board
------
id INT PK

officer
------
id INT PK

If you’re into OOP, Officer Inherits Board Inherits Member. In other words, if someone is listed on the officer table, s/he is listed on the board table and the member table. I want to find out the highest privilege level someone has. So far my SP looks like this:

DELIMITER //
CREATE PROCEDURE GetAuthLevel(IN targetID MEDIUMINT)
    BEGIN
        IF 
            SELECT `id`
            FROM `member`
            WHERE `id` = targetID;
        THEN
            IF
                SELECT `id`
                FROM `board`
                WHERE `id` = targetID;
            THEN
                IF
                    SELECT `id`
                    FROM `officer`
                    WHERE `id` = targetID;
                THEN
                    RETURN 3; /*officer*/
                ELSE
                    RETURN 2; /*board member*/
            ELSE
                RETURN 1; /*general member*/
        ELSE
            RETURN 0; /*not a member*/
    END //

DELIMITER ;

The exact text of the error is
#1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near

    'SELECT id
    FROM member
    WHERE id = targetID;
THEN
    IF
        SEL' at line 4 

I suspect the issue is in the arguments for the IF blocks. What I want to do is return true if the result-set is at least one — i.e. the id was found in the table.

Do any of you guys see anything to do here, or should I reconsider my database design into this:?

person
------
id INT PK
level SMALLINT

Answer 1

CREATE PROCEDURE GetAuthLevel(IN targetID MEDIUMINT)
    BEGIN

    DECLARE var INT;

    SELECT `id` INTO var
    FROM `member`
    WHERE `id` = targetID;

    IF var IS NOT NULL THEN
        ...