请解释如何使用派生表将此SQL表示为单个语句

这里有些东西,虽然坏了,但和我想要的差不多:

SELECT split.share, split.weight, split.creditor, split.debtor, share.amount, wsum.sum
FROM (
    SELECT split.share, split.weight, split.creditor, split.debtor, share.amount
    FROM ( split LEFT JOIN share ON split.share = share.id )
    WHERE debtor = 6 OR creditor = 6 )
    LEFT JOIN (
        SELECT split.share, SUM(weight) AS sum
        FROM split
        GROUP BY split.share
    ) wsum
    ON split.share = wsum.share;

CREATE TEMPORARY TABLE weightsum (share INT, sum INT);

INSERT INTO weightsum (share, sum)
SELECT split.share, SUM(weight) AS sum
FROM split
GROUP BY split.share;

CREATE TEMPORARY TABLE summary (share INT, weight INT, creditor INT, debtor INT, amount DECIMAL(10,2));

INSERT INTO summary (share, weight, creditor, debtor, amount)
SELECT split.share, split.weight, split.creditor, split.debtor, share.amount
FROM (split LEFT JOIN share ON split.share = share.id)
WHERE debtor = 6 OR creditor = 6;

SELECT summary.share, summary.weight, weightsum.sum, summary.creditor, summary.debtor, summary.amount, ((summary.amount / weightsum.sum) * summary.weight) AS split_amount
FROM summary LEFT JOIN weightsum
ON summary.share = weightsum.share;

谢谢你的帮助。