具有count(*)的Update子句

SELECT a.protocol_number, b.STATUS_NAME, COUNT(*) FROM PARTICIPANTS a LEFT JOIN PROTOCOLS b ON a.PROTOCOL_NUMBER = b.PROTOCOL_NUMBER GROUP BY a.PROTOCOL_NUMBER, b.STATUS_NAME HAVING count(*) = 1 AND b.STATUS_NAME = 'OPEN';

我想将这些协议的状态更新为CLOSED,但找不到运行正常的查询。我试过这个但它永远挂着:

UPDATE
    PROTOCOLS p1
SET
    p1.STATUS_NAME = 'CLOSED'
WHERE
    p1.protocol_Number IN (
    SELECT
        PROTOCOL_NUMBER
    FROM
        (
        SELECT
            a.protocol_number, b.STATUS_NAME, COUNT(*)
        FROM
            PARTICIPANTS a
        LEFT JOIN PROTOCOLS b ON
            a.PROTOCOL_NUMBER = b.PROTOCOL_NUMBER
        GROUP BY
            a.PROTOCOL_NUMBER, b.STATUS_NAME
        HAVING
            count(*) = 1
            AND b.STATUS_NAME = 'OPEN');