I've been a professional C, Perl, PHP and Python developer.
I'm an ex-sysadmin from the late 20th century.
These days I do more Javascript and CSS and whatnot, and promote UX and accessibility.
I did exactly the same one time, where I used to be "careful" by writing everything as SELECTs first before changing them to UPDATEs, making extensive use of the command-line history. I ended up writing UPDATE users SET first_name='Martin'; WHERE user_id=12345. Clever me and my semicolons. It replicated 10,000+ changes to 300+ other sites and took down the whole system in short order. I tell that story in interviews when they ask for nightmare stories.
I did exactly the same one time, where I used to be "careful" by writing everything as SELECTs first before changing them to UPDATEs, making extensive use of the command-line history. I ended up writing
UPDATE users SET first_name='Martin'; WHERE user_id=12345. Clever me and my semicolons. It replicated 10,000+ changes to 300+ other sites and took down the whole system in short order. I tell that story in interviews when they ask for nightmare stories.Wow, that's one heck of a story!