Hi,
Some databases (like Teradata) support the following syntax:
select col1, col2*20 as col2_1, col2_1*200 as col3_1 from your_table;
The last element in the target list can refer the second one using its alias.
This feature is similar to some programming languages (like Lisp)'s let*.
For Postgres, it seems the only way is to write a subquery and then a new target list.
Will Postgres plan to support this feature?
Thanks a lot!