My adventures in code & business
As the Junior Data Scientist of Knight Industries we created a table to keep track of all our operatives: SQL-Basics: Create, Read, Update, Delete
Devon asks us to keep track of our operations aka missions as well. For the first implementation let us assume that a mission has one operative and an operative can participate in multiple missions. that’s what we call an 1 to many relationship. Continue reading “SQL-Basics: Relations”
Sometimes your RDBMS does not allow you to do certain changes like updating a table without using a WHERE clause that uses a key column.
When you are really sure what you want to do:
SET SQL_SAFE_UPDATES = 0;
Now the dirty brown magic can begin!
Back to the SQL-Tutorial
Sometimes You screw up your database design and you have redundancies i.e. your database is not normalized. If You want to correct that: Subqueries for the rescue! Continue reading “SQL-Basics – Subqueries: Update column with values from another column”