Another trick is, if you're programmatically building a SQL statement - adding "WHERE 1=1" makes things easier ... like so:

  SELECT *
  FROM table
  WHERE 1=1

That way, if you want to filter down the result, everything programmatically appended just needs an "AND ..." at the start, like:

  SELECT *
  FROM table
  WHERE 1=1
  AND age > 21
  AND xyz = 'abc' ...

Because without "WHERE 1=1", you'd had to handle the first condition different than all subsequent conditions.