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Tag: database

Find missing rows between three related tables

I have three tables: Person Dates Absence I need to find all of the person_id’s in the Person table and the date’s from the Dates table who have not booked any absence matching the following criteria: Dates.date_type = ‘PUBLIC_HOLIDAY’ Absence.absence_type = ‘HOLIDAY’ Basic…

Convert this SQL into eloquent ORM

I want to convert the following sql statement into eloquent: I did this as like below: The problem is that it is converting to the same sql but showing error. The error is shown below: * order_number, order_id, sum(quantity) as qty, sum(price) as pr from orders right join order_details on orders.id = order_de…

Best technology for building race simulation application

I am trying to do something new, something I have never done before. I am looking for advice or point me into right direction how to choose technology. I am trying to build race simulation app that will have thousands of iot devices streaming data into central platform. While I understand that I can use some …

Group by not getting the expected results in mysql

I have the next query: That is working perfectly and returning 9 rows: I want to group the results by boat type and get the number of boats per type. However, when I do: I´m getting: but according to the first query, I´m expecting What am I missing? Answer I suspect that you want: That is: move the DISTINCT w…

using condition for Group_Concat

I want to find all ids of which group_concat only contains ‘a’. Here is simplified table from mine. ╔════╦══════════════╦ ║ id ║ group_concat ║ ╠════╬══════════════╬ ║ 1 ║ a,b,b ║ ║ 2 ║ a …