关于匹配度查询

SELECT
    a.*,
    CONCAT(
        TRUNCATE ((
            IF
                ( ISNULL( b.id ), 0, 1 )+
            IF
                ( ISNULL( c.id ), 0, 1 )+
            IF
                ( ISNULL( d.id ), 0, 1 ))/ 3 * 100,
            0 
        ),
        '%' 
    ) AS ratio 
FROM
    users a
    LEFT JOIN ( SELECT id FROM users WHERE sex = '男' ) b ON a.id = b.id
    LEFT JOIN ( SELECT id FROM users WHERE education = '本科' ) c ON a.id = c.id
    LEFT JOIN ( SELECT id FROM users WHERE city = '广州' ) d ON a.id = d.idCopy