GHI

[1] || means "or" ↳ OR ,  ||  Logical OR. Returns 1 if either argument is not 0 and not NULL.
[2] ! means not() ↳ NOT , !   Logical NOT. Returns 1 if the argument is 0
[3] {f} means timestamp .

Comparison operators : If one of the arguments is a TIMESTAMP or DATETIME column and
the other argument is a constant, the constant is converted to a timestamp before the comparison
is performed. This is done to be more ODBC-friendly.

[4] `id` is the column .
[5] --%0a means comment and new line .
[6] the @ after is just to stick a char to select, @ is a temporary variable .