Over the New Year holidays, I decided to refresh my SQL theory. I remembered that I’d once been recommended a course by SQL Academy, and thought — why not, this is the perfect time. The course is ...

-- windows functions are really powerful and are somewhat like a group by - except they don't roll everything up into 1 row when grouping. -- windows functions allow us to look at a partition or a ...

-- a Trigger is a block of code that executes automatically executes when an event takes place in a table. -- for example we have these 2 tables, invoice and payments - when a client makes a payment ...