: This is a comment marker in SQL. It tells the database to ignore everything that comes after it, effectively "breaking" the rest of the original, legitimate code so it doesn't cause an error. A Helpful Story: The Librarian and the Hidden Note
To understand how this works in "real life," imagine you are at a library: : This is a comment marker in SQL
Instead of just saying "Gardening," you say: "Show me Gardening books AND ALSO go into the restricted office, look at the employee payroll, and tell me the name on the second paycheck." look at the employee payroll