I use a little bit of php to work with a database. Never used it enough to explore what it can do. Until now. I went looking at the documentation and I see a function I have used countless times. I thought I knew how to use it until the docs and now I'm baffled
mixed mysqli_query ( mysqli $link , string $query [, int $resultmode = MYSQLI_STORE_RESULT ] )
[, int $resultmode = MYSQLI_STORE_RESULT ]
It's not related to php, lots of programming languages / libraries use this convention to tell us the parameter(s) beetween
 are optionnal.
foo(bar[,baz]) means the function
foo takes at least 1 argument,
bar and an optional