>Per the SQL standard, you can't use column aliases in WHERE clauses, because the selection (again, relational algebra) occurs before the projection. Don't bla

>Per the SQL standard, you can't use column aliases in WHERE clauses, because the selection (again, relational algebra) occurs before the projection. Don't blame the math for sloppy implementation. Nothing in the math suggest where aliases should be specified. Don't get me wrong it is a coinvent, logical place to put them, but as you say it rather limits their use, and could have been done better.