Question

我用 -

创建了一个表

width + padding + border = actual visible/rendered width of an element's box,
height + padding + border = actual visible/rendered height of an element's box.

在其中插入了一些值并尝试使用此查询

CREATE TABLE sales(year INT, country VARCHAR(20), product VARCHAR(32), profit INT);

获得的结果 -

SELECT GROUP_CONCAT(country) as country, year, SUM(profit) AS profit
FROM sales
GROUP BY year ASC WITH ROLLUP;

如图所示 - 最后一行连接所有行值。有没有办法我可以用NULL替换最后一行的值，就像年份一样？

我需要country | year | profit ----------------------------------------------|-------|---------- India,Australia | 2014 | 50 ----------------------------------------------|-------|---------- New Zealand | 2015 | 20 ----------------------------------------------|-------|---------- United States | 2016 | 150 ----------------------------------------------|-------|---------- India,Australia,New Zealand,United States | NULL | 220使用GROUP_CONCAT而不能country groupby获取country。只想用空的val替换最后一行值。

Answer 1

你应该避免汇总

  select country, year, profit
  from (
    SELECT '1' seq, GROUP_CONCAT(country) as country, year, SUM(profit) AS profit
    FROM sales
    GROUP BY seq, year ;

    union 

    select '2', null, null, SUM(profit)
    SELECT 
    FROM sales
  ) t
  order bt t.seq, t.country

Answer 2

GROUP BY WITH ROLLUP使用起来有点棘手，有时你会得到奇怪的结果。

我建议您使用UNION和第二个查询来获得所需的结果。

SELECT GROUP_CONCAT(country) as country, year, SUM(profit) AS profit
FROM sales
GROUP BY year ASC

UNION ALL 

SELECT NULL, NULL, SUM(profit) AS profit FROM sales

with_concat with rollup搞砸了最后一行

2 个答案: