MariaDB 10.2

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CREATE TABLE members
(
    memberid integer PRIMARY KEY,
    name varchar(100)
) ;
INSERT INTO members
    (memberid, name)
VALUES
    (1, 'member 1'),
    (2, 'member 2') ;
CREATE TABLE fees
(
    memberid integer REFERENCES members(memberid),
    amountpaid decimal(10,2) NOT NULL,
    paiddate date NOT NULL
) ;
INSERT INTO fees
   (memberid, amountpaid, paiddate)
VALUES
   (1, 100.0, curdate()),
   (2, 100.0, curdate() - interval 1 month);
SELECT * FROM fees JOIN members ON fees.memberid = members.memberid;


memberid
amountpaid
paiddate
memberid
name


1
100.00
2020-01-20
1
member 1

2
100.00
2019-12-20
2
member 2


SELECT
    memberid, name
FROM
    members
WHERE
    memberid NOT IN
    (SELECT
        memberid
    FROM
        fees
    WHERE
        YEAR(paiddate) = YEAR(curdate()) AND
        MONTH(paiddate) = MONTH(curdate())
    )


memberid
name


2
member 2