Mysql 选择而不分组

如何在不分组的情况下获得结果

我的桌子

id  user_id amount  currency_id type    status
5   2   2.00    1   0   0
6   3   3.00    1   0   0
4   1   1.00    1   0   0
7   4   4.00    1   0   0
8   5   3.00    1   1   0

我做以下选择

SELECT id, user_id, amount, currency_id, SUM( amount ) 
FROM market
WHERE amount <=3
AND type = 0
AND status = 0

如何获得此结果：

id  user_id amount  currency_id SUM( amount )
5   2   2.00    1   0   6.00
6   3   3.00    1   0   6.00
4   1   1.00    1   0   6.00

给你：

SELECT id, user_id, amount, currency_id, t2.total
FROM market, (
    SELECT SUM(amount) AS total
    FROM market
    WHERE amount <=3
    AND type = 0
    AND status = 0
) AS t2
WHERE amount <=3
AND type = 0
AND status = 0

你可以加入

SELECT  id, 
        user_id, 
        amount, 
        currency_id, 
        a.totalAmount
FROM    market
        CROSS JOIN
        (
            SELECT SUM(amount) totalAmount
            FROM    market
            WHERE   amount <=3
                    AND type = 0 
                    AND status = 0
        ) a
WHERE   amount <=3
        AND type = 0 
        AND status = 0

或者使用内联子查询

SELECT  id, 
        user_id, 
        amount, 
        currency_id, 
        (
            SELECT SUM(amount) totalAmount
            FROM    market
            WHERE   amount <=3
                    AND type = 0 
                    AND status = 0
        ) totalAmount
FROM    market
WHERE   amount <=3
        AND type = 0 
        AND status = 0

---

如果您的目的是返回满足此条件的单个记录并对其进行汇总，而实际上不需要将汇总值作为每行的字段，也不知道为什么要这样做，那么我建议您通过以下方式查看组。。。使用“上卷”修改器。它的工作原理如下：

SELECT id, user_id, SUM(amount) AS `amounts`, currency_id
FROM market
WHERE amount <=3
AND type = 0
AND status = 0
GROUP BY id WITH ROLLUP

id    user_id amounts  currency_id
5     2       2.00    1
6     3       3.00    1
4     1       1.00    1
NULL  3       6.00    1

注意，最后一条记录提供了SUM函数的汇总。还请注意，汇总行中的user_id和currency_id的值是不确定的，因为它们不是GROUP BY或聚合的一部分。因此，它们没有任何意义。

如果您不想分组，请不要使用SUM。您正在尝试获取查询中所有记录的总和吗？我想我不知道每行6.00美元是从哪里来的。

id    user_id amounts  currency_id
5     2       2.00    1
6     3       3.00    1
4     1       1.00    1
NULL  3       6.00    1