Question

我有以下 solditems 表

+---------+--------+----------+
| orderid | itemid | unitsold |
+---------+--------+----------+
| 1       | ITEM1  | 2        |
+---------+--------+----------+
| 2       | ITEM2  | 5        |
+---------+--------+----------+
| 3       | ITEM1  | 1        |
+---------+--------+----------+
| 4       | ITEM3  | 1        |
+---------+--------+----------+

我需要在我的统计信息页面上找到以下值。

销售总量
仅售出一次的商品总数
多次售出的商品总数

查询第一个问题

SELECT sum(unitsold) AS total FROM solditems;

对于第二个问题，我使用以下查询

SELECT 
    itemid, SUM(unitsold) AS total
FROM
    solditems
GROUP BY itemid
ORDER BY total DESC;

获得以下结果

+--------+-------+
| itemid | total |
+--------+-------+
| ITEM2  | 5     |
+--------+-------+
| ITEM1  | 3     |
+--------+-------+
| ITEM3  | 1     |
+--------+-------+

对于问题2，我如何得到答案 1 ，因为只有一个项目 ITEM3 只卖一次

对于问题3，我如何得到答案 2 ，因为两个项 ITEM1 和 ITEM2 多次出售。

我可以在查询中使用“HAVING”列出一次又一次销售的商品。

SELECT 
    itemid, SUM(unitsold) AS total
FROM
    solditems
GROUP BY itemid
HAVING total = 1
ORDER BY total DESC;

获取仅售出一次的商品。

+--------+-------+
| itemid | total |
+--------+-------+
| ITEM3  | 1     |
+--------+-------+

和

SELECT 
    itemid, SUM(unitsold) AS total
FROM
    solditems
GROUP BY itemid
HAVING total > 1
ORDER BY total DESC;

获取多次售出的商品。

+--------+-------+
| itemid | total |
+--------+-------+
| ITEM2  | 5     |
+--------+-------+
| ITEM1  | 3     |
+--------+-------+

我应该如何修改我的查询以获得以下答案。

问题2：答案总数= 1 [即仅出售一次的物品总数]

问题3：答案总数= 2 [即多次出售的物品总数]

ANSWER

问题2：

SELECT 
    COUNT(DISTINCT itemid) AS total
FROM
    solditems
WHERE
    itemid IN (SELECT 
            itemid
        FROM
            solditems
        GROUP BY itemid
        HAVING SUM(unitsold) = 1);

问题3：

SELECT 
    COUNT(DISTINCT itemid) AS total
FROM
    solditems
WHERE
    itemid IN (SELECT 
            itemid
        FROM
            solditems
        GROUP BY itemid
        HAVING SUM(unitsold) > 1);

我得到答案，但想检查是否有更好的方法来做到这一点。

Answer 1

您可以从MySQL中的选择
计算

SELECT 
    COUNT(*) AS amount_sold_once
FROM
    (SELECT 
        itemid, SUM(unitsold) AS total
    FROM
        solditems
    GROUP BY itemid
    HAVING total = 1
    ORDER BY total DESC) AS sold_once

请注意您要计算的select语句在圆括号（）中，并有自己的别名。

Answer 2

您必须在查询中添加HAVING部分。

    SELECT 
        itemid, SUM(unitsold) AS total
    FROM
        solditems
    GROUP BY itemid HAVING SUM(unitsold) > 1
    ORDER BY total DESC;

Answer 3

对于您的问题2.尝试此查询。

SELECT 
    itemid, count(itemid) AS total
FROM
    solditems
GROUP BY itemid HAVING  total= 1

对于问题3，试试这个

SELECT 
    itemid, count(itemid) AS total
FROM
    solditems
GROUP BY itemid HAVING  total>1

Answer 4

您可以尝试此查询

select itemid ,sum(unitsold) as unitsold from solditems 
where itemid in(select distinct(itemid )
 from solditems) orderby unitsold asc;

MySQL - 计算出售ITEMS的次数 - 管理员统计页面

4 个答案: