MySQL COUNT in two tables same time
My question is not so hard, i just really can't find the answer anywhere.
I've got 3 tables.
webshops
, webshop_category
and webshop_item
.
My query is:
SELECT we开发者_StackOverflow中文版bshops.id, webshops.name, webshops.tax, webshops.contact_name, webshops.contact_email, webshops.contact_phone, webshops.contact_address, COUNT(webshop_category.id), COUNT(webshop_item.id)
FROM webshops, webshop_category, webshop_item
WHERE webshops.id = webshop_category.ws_id AND webshop_category.id = webshop_item.ws_category
GROUP BY webshops.id
My #1 webshop got 2 categories with 4 items. But with this query it says:
id ... COUNT(webshop_category.id) COUNT(webshop_item.id)
1 4 4
But i just have 2 categories. So i'd like it to be:
id ... COUNT(webshop_category.id) COUNT(webshop_item.id)
1 2 4
How can i do this?
Thanks for the help.
Use a COUNT(DISTINCT webshop_category.id) that should do it in this case.
put a distinct inside the count like:
SELECT webshops.id, webshops.name, webshops.tax, webshops.contact_name, webshops.contact_email, webshops.contact_phone, webshops.contact_address, COUNT(DISTINCT webshop_category.id), COUNT(webshop_item.id)
FROM webshops, webshop_category, webshop_item
WHERE webshops.id = webshop_category.ws_id AND webshop_category.id = webshop_item.ws_category
GROUP BY webshops.id
精彩评论