MySQL check if subquery return NULL, then replace value

Question

I have mysql query where I need to replace value in WHERE clause if subquery returns no results or null value.

Price query which works as required

Runs Successfully

SELECT `prices` FROM `pricing`
WHERE (3 BETWEEN `from_unit` AND `to_unit`)
AND `type` = 1
AND `id_pricing` IN 
    (   
        SELECT v1.`id_pricing` FROM `values` AS v1
        INNER JOIN `values` AS v2 ON v1.`id_pricing` = v2.`id_pricing`
        INNER JOIN `values` AS v3 ON v1.`id_pricing` = v3.`id_pricing`
        INNER JOIN `values` AS v4 ON v1.`id_pricing` = v4.`id_pricing`
        WHERE v1.`id_attribute` = 1 AND v1.`id_value` = 1
        AND v2.`id_attribute` = 7 AND v2.`id_value` = 63
        AND v3.`id_attribute` = 8 AND v3.`id_value` = 87
        AND v4.`id_attribute` = 12 AND v4.`id_value` = 143  
    )

when I modify this query as below, adding IFNULL check on subquery inside IN clause, it throws error

'SQL Error (1242): Subquery returns more than 1 row'

SELECT `prices` FROM `pricing`
WHERE (3 BETWEEN `from_unit` AND `to_unit`)
AND `type` = 1
AND `id_pricing` IN 
    (   IFNULL  (
                    (   SELECT v1.`id_pricing` FROM `values` AS v1
                        INNER JOIN `values` AS v2 ON v1.`id_pricing` = v2.`id_pricing`
                        INNER JOIN `values` AS v3 ON v1.`id_pricing` = v3.`id_pricing`
                        INNER JOIN `values` AS v4 ON v1.`id_pricing` = v4.`id_pricing`
                        WHERE v1.`id_attribute` = 1 AND v1.`id_value` = 1
                        AND v2.`id_attribute` = 7 AND v2.`id_value` = 63
                        AND v3.`id_attribute` = 8 AND v3.`id_value` = 87
                        AND v4.`id_attribute` = 12 AND v4.`id_value` = 143
                    ),  
                    '1234'
                )
    )

I tried replacing IFNULL with COALESCE still same result. Am I using wrong syntax.

Answer 1

Possibly move it to a LEFT JOIN and check that either there is a record, or that pricing is 1234:-

SELECT `prices` 
FROM `pricing`
LEFT OUTER JOIN
(
    SELECT v1.`id_pricing`, COUNT(*)
    FROM `values` AS v1
    INNER JOIN `values` AS v2 ON v1.`id_pricing` = v2.`id_pricing`
    INNER JOIN `values` AS v3 ON v1.`id_pricing` = v3.`id_pricing`
    INNER JOIN `values` AS v4 ON v1.`id_pricing` = v4.`id_pricing`
    WHERE v1.`id_attribute` = 1 AND v1.`id_value` = 1
    AND v2.`id_attribute` = 7 AND v2.`id_value` = 63
    AND v3.`id_attribute` = 8 AND v3.`id_value` = 87
    AND v4.`id_attribute` = 12 AND v4.`id_value` = 143
    GROUP BY v1.`id_pricing`
) Sub1
ON Sub1.id_pricing = pricing.id_pricing
WHERE (3 BETWEEN `from_unit` AND `to_unit`)
AND `type` = 1
AND (Sub1.`id_pricing` IS NOT NULL
OR pricing.id_pricing = '1234')