mysql - 如何查询group by 2条件？

Question

我这里有 table 。

我怎么能

SELECT 
    sum(gload1) as 'g1',
    sum(gload2) as 'g2'.
    sum(gload3) as 'g3',
    sum(gload4) as 'g4' 
FROM member 
WHERE age = 15-20,21-25,26-30 
GROUP BY gender;

结果是这样的:只是样本

我怎样才能这样查询。感谢您的进步。

Answer 1

SELECT 
  CASE 
    WHEN `age`>=15 AND `age`<=20 THEN '15-20'
    WHEN `age`>=21 AND `age`<=25 THEN '21-25'
    WHEN `age`>=26 AND `age`<=30 THEN '26-30'
  END AS `AgeRange`,
  SUM(`gload1`) AS `g1`, 
  SUM(`gload2`) AS `g2`, 
  SUM(`gload3`) AS `g3`, 
  SUM(`gload4`) AS `g4`
FROM 
  member 
GROUP BY `AgeRange`

参见 SQL Fiddle