SQL查询-选择不同的类别和数量

Question

I am working on a SQL query where I select distinct category and count how many rows in x category. I want to achieve a result like:

X.category | Amount
--------------------
Hi         | 3
--------------------
Hello      | 2
--------------------

SELECT DISTINCT company.category,  category.desc2 FROM company, category

This query works but lacks amount (count).

Answer 1

I think the code your looking for is the GROUP BY -clause.

SELECT DISTINCT company.category, COUNT(*) 
FROM company, category
GROUP BY company.category

You can read more about in the docs .

Answer 2

Try this query

SELECT  company.category,  count(*) FROM company, category
Where company.category=Category.category
Group By company.category

Answer 3

好的，我想我已经针对自己的问题提出了解决方案。

SELECT DISTINCT company.category, count(DISTINCT company.id) as amount, category.name, category.desc2 FROM company, category WHERE company.category = category.name GROUP BY company.category;