I’m working on the following user table, where role = 2 means the user is an instructor, and role = 3 means that the user is a student. My goal is to select the sum value of all instructors and students, grouped by date. The result should look like this: In this case, on 2020-07-01, I had 1 instructor a…
Tag: mysql
get records that last record binded with it have a specific value
I have this case where there is 2 tables: book for example and loan for example: I need to get all books id , where the last loan duration equals , so in this example it will be : [1,2] Answer One method uses aggregation: This checks that the last id for a given book matches the last id for
Doing a simple join on two tables
I have the following two tables: team: game: I am trying to attain this output: I can do a simple join to receive one of the team names, but how do I get both names in one query? Answer Try this: You just need to join with the table “team” twice.
Calculating the win/loss ratio per team
I have the following two tables: sport_a_statistics: id team_id game_id points 1 1 1 7 2 2 1 8 3 3 2 6 …
How do I preserve utf-8 JSON values and write them correctly to a utf-8 txt file in Python 3.8.2?
I recently wrote a python script to extract some data from a JSON file and use it to generate some SQL Insert values for the following statement: The names of some of the attributes are different in my SQL table but the same values are used (example cardClass in the JSON file/Python script is referred to as c…
You have an error in your SQL syntax when i have single comas and |
I’m new to sql, trying to insert values in my table INSERT INTO table1 VALUES (1, ALL||test > test’s done> test’s done again’s done||test > test’s done> test’s done again’s done 2,new); …
Is there a way to enforce the MySQL CHECK constraint for calculated value
Apologies if my wording is very awkward/non-fitting for a programmer – I’m just a SQL noob who’s taking a beginners’ class. I’m using PHPMyAdmin to design an e-commerce database in which the minimum age of a customer is 18 yo. Because age is a calculated column, I want to record …
MySQL: Why are these two wrong? (Invalid use of group function, selected nothing after using having())
Credit:Leetcode_1076.Project Employees II Here is the sample table Project table: (project_id, employee_id) is the primary key of this table. I have tried several methods and managed to find the right one by using dense_rank(); however, I still don’t understand why these two syntaxes are wrong to select…
How to SELECT two records for each unique column value as one row in MySQL?
I have a MySQL table like this : +—-+—–+——-+——+——+——-+———————+ | ID | GID | Name | p1 | p10 | p100 | createdAt | +—-+—–+——-+——+——+—-…
Using top N in sql
statement 1 statement 2 I have tried the above but both are not working. Does anybody know the reason? Answer If you want to update one row, then you can use limit: That said, I would expect id to be unique, so no LIMIT is necessary.