Re: Classic trap : using SQL while not fully competent

[Joe Pluta <joepluta@xxxxxxxxxxxxxxxxx>]

Elvis Budimlic wrote:
> > [Joe wrote] I'm not sure why this gets past the syntax checker;
> >     
>
> It is a valid syntax, except it wasn't what OP was after in his scenario.
>   
Why is it valid?  If it's an exception join, the only possible values in 
the right-hand file are null.  WHERE field=null is always true, WHERE 
field=(anything but null) is always false, and, if you were going to 
allow it at all, should end the query right there since nothing will 
every match.

Then again, SQL considers SELECT * FROM FILE WHERE '1' = '0' to be valid 
syntax, so I guess it only follows that the WHERE clause wouldn't cause 
it to fail.

Joe