我正在嘗試通過兩個約束（user_id 和符號）對記錄表進行 SUM 計算，并將值存盤到另一個名為 calculation 的表中。我嘗試以下操作但它不起作用。誰能給我一些建議？
UPDATE records, calculation
SET calculation.sumOfAmount=sum(records.amount)
WHERE records.user_id=calculation.user_id AND records.symbol=calculation.symbol
uj5u.com熱心網友回復：
UPDATE calculation c
JOIN
(
SELECT user_id, symbol, sum(amount) as sum_amount
FROM records
GROUP BY user_id, symbol
) r ON r.user_id = c.user_id AND r.symbol = c.symbol
SET c.sumOfAmount = r.sum_amount
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