获取Access中一列中不同值的数量

Question

我或多或少地尝试了 count 和 distinct 的所有组合（正确的组合除外 :)）以获得下面的示例。

输入：tablet1

NAME       |  FOOD
Mary       |  Apple
Mary       |  Banana
Mary       |  Apple
Mary       |  Strawberry
John       |  Cherries

预期输出：

 NAME      |  FOOD
Mary       |  3
John       |  1

N.B。玛丽有两行苹果，但她有 3 行，因为我们在列中有 3 个不同的值。我只设法为她在 FOOD 栏中获得 4 个，但我需要 3 个 :(

Answer 1

select a.name as NAME, a.count(name) as Food 
from 
(SELECT distinct NAME,Food from table)a

Answer 2

从一个查询开始，该查询为您提供 NAME 和 FOOD:

的独特组合

SELECT DISTINCT t1.NAME, t1.FOOD
FROM t1

然后您可以将其用作另一个子查询，您可以在其中使用 GROUP BY 和 Count:

SELECT sub.NAME, Count(*) AS [FOOD]
FROM
    (
        SELECT DISTINCT t1.NAME, t1.FOOD
        FROM t1
    ) AS sub
GROUP BY sub.NAME;

Answer 3

select a.name, sum(a.FoodCount) from(
select distinct name,COUNT(food) as FoodCount from #t1 group by name, food ) as a group by a.name order by 2 desc

获取Access中一列中不同值的数量

Get number of different values in a column in Access

sql

ms-access

count

distinct