Question

我有2张桌子。 t1和t2

以下数据为t1，kid为planID，uid为Userid，buytime为购买数量。

+---------+-------------+-------------+---------------+
| kid     | uid         | buytime1    | buytime2      |
+---------+-------------+-------------+---------------+
| 1       | 1           | 10          | 5             |
| 1       | 2           | 1           | 0             |
| 1       | 3           | 3           | 5             |
| 2       | 4           | 1           | 10            |
| 3       | 5           | 20          | 6             |
+---------+-------------+-------------+---------------+

t2数据：

+---------+-----------+-----------+
| ID      | costb1    | costb2    |
+---------+-----------+-----------+
| 1       | 100       | 200       |
| 2       | 300       | 500       |
| 3       | 1000      | 2000      |
+---------------------------------+

我想在mysql中执行SUM，如：

SUM buytime1 * costb1 + buytime2 * costb2 Where t1.kid = t2.id

$query = DB::query("SELECT SUM(something like buytime1 * costb1 + buytime2 * costb2) FROM ".DB::table('t1')." t1 LEFT JOIN ".DB::table('t2')." t2 ON (t1.kid = t2.id)");

因此最终结果应为40700

10 * 100 + 5 * 200 = 2000
1 * 100 + 0 * 200 = 100
3 * 100 + 5 * 200 = 1300
1 * 300 + 10 * 500 = 5300
20 * 1000 + 6 * 2000 = 32000

那么我应该在query编辑我的编码？

Answer 1

只需使用您提供的devtools::install_github('trinker/plotflow') library(plotflow) d1 = data.frame(x = rnorm(15),y = rnorm(15)) d2 = data.frame(x = rnorm(15),y = rnorm(15)) plotflow::ggdual_axis( ggplot(data = d1, aes(x= x,y =y))+geom_line(), ggplot(data = d2, aes(x= x,y =y))+geom_line() ) - 这将导致40700：

sum

SQL Fiddle Demo

不确定您是否需要select sum((t1.buytime1 * t2.costb1) + (t1.buytime2 * t2.costb2)) from t1 join t2 on t1.kid = t2.id - 如果是，那么您需要定义这些缺失值应该相等的内容。如果需要，使用outer join应该有帮助。

Mysql Php Sum（）乘法？

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