> it won't do any good ...
Here is your last posted SQL in this thread, annotated:<code>
select -- This is the "outer SELECT" here.
EG, -- Creates a tuple element named EG as projected from this outer SELECT. [a]
-- It uses well-defined projected tuple element EG from the inner SELECT.
GPVBW/1000000-EG as Diff, -- Creates <i>ditto</i> named Diff as <i>ditto</i>
-- It uses ... elements named EG and GPVBW from inner Select (or fails)
Delay -- Creates a tuple element named Delay as projected from this outer SELECT
-- It uses ... element named Delay from inner Select (or fails)
-- None of the above names used in expressions (or lone terms) binds to any of
-- the tuple elements projected from this outer SELECT. They can only bind to
-- named tuple elements projected from the below inner SELECT.
from (
select -- This is the "inner SELECT" here.
\*, -- Presumably, this creates GPVBW and Delay as projected tuple elements.
TID\*0.003\*250 as EG, -- Creates EG projected from this inner SELECT
Diff/0.003/250/750\*60 -- Creates a projected tuple element with a poorly
-- defined name which is hard to use and useless here.
from CalculateGrowth
)
</code>
This is very fundamental to using SELECT, so I encourage you to study and understand the name scoping (or possible binding) rules in effect as noted above.
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\[a. This is per convention; SQL language definition does not require it. \]