I an using c# and mysql server and i have two tables like this : table_1 +--------+----------------------+-----------+----------------+ | aut_id | aut_name | country | home_city | +--------+----------------------+-----------+----------------+ | AUT001 | William Norton | UK | Cambridge | | AUT002 |…
I need help regarding my sql project. I have a table in which football results in column as VARCHAR. And I want to make it impossible to insert data into them other than in this format: number:number For example: 2:1,…
My PHP code iterates a big MySQL table using PDO and an unbuffered connection: SELECT ID,X,Y FROM tbl WHERE Z IS NULL. For every row, it updates a field Z with the result of op(X,Y). Only rows where Z is…
I have this simple structure in my database CREATE TABLE species ( _id INTEGER PRIMARY KEY, name TEXT NOT NULL ); CREATE TABLE compatibility ( _id INTEGER PRIMARY KEY, speciesA INTEGER, speciesB INTEGER, compatibility TINYINT NOT NULL ); I want…
I am using PHP 8.1 and MySQL 8.0. All databases, tables and individual fields are all set to a collation of utf8mb4_0900_ai_ci - except for databases: information_schema and performance_schema, which are utf8mb3_general_ci (system default?). Here are the global variables MySQL…
Does MySQL have any aliasing capabilities for column/table names without specifying them in the query? For example, Let's pretend I have a very complex application talking to an equally complex schema that's been touched by many hands over the years.…
I have one MySQL instance with one database for each user. I want to build an API that should connect to the right database depending on the user calling it. For this setup what is the best way to manage…
I have the following table structure/data: id date (DATE) hour (INT) tally (INT) sum (INT) 1 2023-05-15 7 12 2 2 2023-05-15 7 1 4 With the following query: SELECT * FROM `table` WHERE ((`date` >= '2023-05-15') AND (`hour` >=…
I have these tables here: and I want to query the store ID with the most purchases in a specific month (any month). I came up with this query: SELECT DISTINCT store_id FROM (SELECT store_id, purchase_date FROM purchase where purchase_date…
I have the following table members: ID hobby 1 Football 1 Tennis 1 Football 2 Cards 2 Painting 3 Tennis 3 Football 4 Cards and i want to select pairs of members only if they have the exact same hobbies…