标签 mysql
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Possible Duplicate:
BIGINT Out-of-range Error since MySQL 5.5
任何人都知道为什么以下会产生 1690 错误:BIGINT UNSIGNED value is out or range?
SELECT CAST(IF(trades.`buyer` = 63, -1, 1) * trades.`price` * trades.`amount` AS SIGNED) AS priceTotal
FROM trades
WHERE (trades.`buyer` = 63 OR trades.`seller`= 63);
我想做的是当用户是买家时使 priceTotal 为负数。
最佳答案
无符号值必须为零或更多 - 所以 -1 超出范围。也许不要使用未签名？
来自data type文档:
BIGINT[(M)] [UNSIGNED] [ZEROFILL]A large integer. The signed range is
-9223372036854775808to9223372036854775807. The unsigned range is0to18446744073709551615.
或者在混合符号上下文中使用每个值时将其转换为有符号的，可能是这样的:
IF(trades.`buyer` = 63, -1, 1) * CAST(trades.`price` AS SIGNED) * CAST(trades.`amount` AS SIGNED)
关于MySQL BIGINT UNSIGNED 值在与 (-1) 相乘时超出范围，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/8104838/