求助'这个试图如何优化？？

Question

主健：SESSION_CODEcreate view->
---------------------------
(
SELECT
    SESSION_CODE,
    SALES_CODE,
    EMPLOYEE_CODE,
    DAY,
    SALES_MANS,
    GUEST_NAME,
    PRODUCT_CODE
FROM
    report
WHERE
    (SELECT
        count(1)
    FROM
        report rep1
    WHERE
        rep1.sales_code = report.sales_code AND
        (rep1.day > report.day or
        (rep1.day = report.day and rep1.session_code > report.session_code)
          )
    ) = 0)

Answer 1

SELECT
    SESSION_CODE,
    SALES_CODE,
    EMPLOYEE_CODE,
    DAY,
    SALES_MANS,
    GUEST_NAME,
    PRODUCT_CODE
FROM
    report
WHERE
    not exists(SELECT 1
    FROM
        report rep1
    WHERE
        rep1.sales_code = report.sales_code AND
        (rep1.day > report.day or
        (rep1.day = report.day and rep1.session_code > report.session_code))
    )

Answer 2

SELECT
    SESSION_CODE,
    SALES_CODE,
    EMPLOYEE_CODE,
    DAY,
    SALES_MANS,
    GUEST_NAME,
    PRODUCT_CODE
FROM
    report
WHERE
    not exists(SELECT 1
    FROM
        report rep1
    WHERE
        rep1.sales_code = report.sales_code AND
        (rep1.day > report.day or
        (rep1.day = report.day and rep1.session_code > report.session_code)
          )