How get values categories an count products for each category in one query?

Question

Table Category :

id    name
1     test1
2     test2
3     test3
4     test4
5     test5

Table Products :

CategoryId      name
1              product1
1              product2
1              product3
1              product4
3              product5
3              product6
3              product7
5              product8
5              product9

For get names category we use:

SELECT Name FROM Category

But how get count products from table Products for each category from table Category in this query with command left join ?

Answer 1

you can use

SELECT category.name, COUNT(category_id) 
FROM category LEFT JOIN product ON category.id = product.category_id
GROUP BY id

and the output will be

test1   4
test2   0
test3   3
test4   0
test4   2