保留前N行数并删除其余行

也许这对您有用(使用Oracle DB)

DELETE FROM
    ZZ_TEST_FINTABLE 
WHERE
    PROCESS_INSTANCE NOT IN 
    (
        SELECT PROCESS_INSTANCE 
        FROM ZZ_TEST_FINTABLE 
        WHERE ROWNUM < 9
    );

您应该使用HAVING而不是AND。

   DELETE 
   FROM ZZ_TEST_FINTABLE
   WHERE PROCESS_INSTANCE = ( 
                            SELECT MIN(B.PROCESS_INSTANCE) 
                             FROM ZZ_TEST_FINTABLE B
                            ) 
   HAVING COUNT(PROCESS_INTANCE) > 9

或者这个

    DELETE 
    FROM ZZ_TEST_FINTABLE A
    INNER JOIN ZZ_TEST_FINTABLE B ON A.PROCESS_INSTANCE= MIN(B.PROCESS_INSTANCE)
    HAVING COUNT(PROCESS_INTANCE) > 9

您必须为您的表修改此项,但应该可以:

DELETE FROM myschema.mytable WHERE pkey NOT IN (SELECT pkey FROM myschema.mytable ORDER BY pkey FETCH FIRST 10 ROWS ONLY)