Column as result of subtraction of two other columns?
От | Mark Cave-Ayland |
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Тема | Column as result of subtraction of two other columns? |
Дата | |
Msg-id | 8F4A22E017460A458DB7BBAB65CA6AE5026611@openmanage обсуждение исходный текст |
Ответы |
Re: Column as result of subtraction of two other columns?
Re: Column as result of subtraction of two other columns? Re: Column as result of subtraction of two other columns? |
Список | pgsql-general |
Hi everyone, I'm trying to calculate an output column which is the difference of two other columns in the query output; the first column is an aggregate of items in stock, while the second column is an aggregate of items which have been used. The third column should should be the difference of the two values so I can then output all three columns in a table. Unfortunately I can't get this to work at the moment :(. I've simplified the query down to the following: dev=# select 1 as a, 2 as b, (b - a) as c; ERROR: column "b" does not exist dev=# Do I need to create some form of alias so the calculation can see the other columns? I am using PostgreSQL 7.4.2 on Linux. Many thanks, Mark. --- Mark Cave-Ayland Webbased Ltd. Tamar Science Park Derriford Plymouth PL6 8BX England Tel: +44 (0)1752 764445 Fax: +44 (0)1752 764446 This email and any attachments are confidential to the intended recipient and may also be privileged. If you are not the intended recipient please delete it from your system and notify the sender. You should not copy it or use it for any purpose nor disclose or distribute its contents to any other person.
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