Question

So say I have a user defined function:

CREATE FUNCTION ADDRESS_EXISTS_FULL (
    line_1 VARCHAR(64),
    line_2 VARCHAR(64),
    city VARCHAR(64),
    state VARCHAR(32),
    zip VARCHAR(10),
    type INT(3)
)
RETURNS INT(1)
DETERMINISTIC
READS SQL DATA
BEGIN
    DECLARE aid INT;

    SET aid = NULL;

    SELECT addressid INTO aid FROM dlp.address as a
        WHERE a.line_1 = line_1
            AND a.line_2 = line_2
            AND a.city = city
            AND a.state = state
            AND a.zip = zip
            AND a.address_type = type
            LIMIT 1;

    RETURN IF(aid IS NOT NULL, 1, 0);

END$$

How do I make it so that some of these are not necessary? Like say if type is not needed, is there anyway to call

 SELECT ADDRESS_EXISTS_FULL(l1,l2,c, s, z)

or would that fail? And how do I make that function work?

Thanks.

Note: I don’t need this function stored, it’s a one off so it’s in one big mysql script file.

Answer 1

You can rewrite the query inside stored function body to something like

SELECT addressid INTO aid FROM dlp.address as a
    WHERE (a.line_1 = p_line_1 OR p_line_1 IS NULL)
        AND (a.line_2 = p_line_2 OR p_line_2 IS NULL)
         --.... etc
        LIMIT 1;

Thus, if you pass null for a particular parameter, it will be ignored. Also, I’d recommend avoiding naming parameters exactly the same as fields in the table – it may lead to very subtle bugs (In the query above I prepended ‘p_’ to each parameter).
Finally, I’d not use DETERMINISTIC keyword for a function that is non-deterministic by nature.