Re: select where true, or select where input = '$var'

 > i want to select based on input, but if input is not provided or if
 > input is empty, then i want to select all rows.

I think you can just use OR:

SELECT  *
FROM    table
WHERE   (input = '' OR input = ?)

This is assuming that `input` is a column in your table and ? is the
user input, based on the query you provided. But are you sure that's
what you mean?

Also, if the `input` column can contain nulls you might also want:

SELECT  *
FROM    table
WHERE   (input IS NULL OR input = '' OR input = ?)

Paul