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Tag: count

MySQL COUNT and IFNULL

I have tables like this: SQLFIDDLE I’m trying to count how many products are in each category SELECT `category_id`, `category_name`, IFNULL(count(*),0) cat_stat FROM `product_to_categories` …

Finding daily registered users

I have a table which includes the information of player_id, first_timestamp, last_timestamp, and date, etc. So I have initially 10 payers on 2020-07-08, and then 18 players on 2020-07-09, some of the players from previous day might appear on 2020-07-09 again. And I’m trying to find the new players registered on 2020-07-09 that did not appear on 2020-07-08, but I

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