对重复的行值求和

Question

我正在尝试对其中两个具有重复值的行的值求和，我拥有的表格如下：

表名（客户）

value   years   total
1           30    30
3           10    10
4           15    15
4           25    25

我希望最终拥有：

value  years   total
1      30      30
3      10      10
4      40      40

我已经尝试使用SELECT DISTINCT 和GROUP BY 来删除重复的行，下面代码中的连接也不是必需的。无论如何，这两个命令都无济于事。这也是我的代码：

SELECT DISTINCT 
  value,
  years,
  SUM(customer.years) AS total 
FROM customer 
INNER JOIN language 
  ON customer.expert=language.l_id 
GROUP BY 
  expert, 
  years;

但这会产生第一个表的副本，欢迎任何输入。谢谢！！！

Answer 1

SELECT
   value,
   SUM(years) AS years,
   SUM(total) AS total
FROM customers
GROUP BY value;

你想要年份的总和和总和，每个 - 分组 - 值。

Answer 2

SELECT 
  value,
  years,
  SUM(customer.years) AS total FROM (SELECT DISTINCT 
  value,
  years,
  customer.years AS total 
FROM customer 
INNER JOIN language 
  ON customer.expert=language.l_id ) as TABLECUS
GROUP BY 
  expert, 
  years;