× The internal search function is temporarily non-functional. The current search engine is no longer viable and we are researching alternatives.
As a stop gap measure, we are using Google's custom search engine service.
If you know of an easy to use, open source, search engine ... please contact support@midrange.com.



On 2/3/11 4:57 PM, Pete Helgren wrote:
I need to select records where the total of some fields is greater
than zero. The field comparisons are from two different tables. Here
is the SQL:

select /* <ed> removed AS clauses */
ixprod,ixdesc,extvin,(lqord-lqshp),coalesce(sqreq-sqfin,0)
from <<SNIP joins; same issue irrespective the nbr of files>>
group by
ixprod,ixdesc,extvin,(lqord-lqshp),coalesce(sqreq-sqfin,0)
having
((coalesce(sqreq-sqfin,0)) - (lqord-lqshp)) > 0
<---- It doesn't like this line

I am running this in an interactive SQL session to test it and it is
complaining about the SQREQ column in the having clause.

<<SNIP>>

What am I missing?


Either side\operand of the predicate which is an expression that includes a column name, must match an expression which is in both the SELECT column\expression list and the GROUP BY column\expression list. The two combined expressions (expr1 - expr2) makes a new arithmetic expression on the left of the less than sign; an expression that appears in neither the SELECT nor the GROUP BY. Thus either that new expression must be added to the SELECT and GROUP BY, or each expression must exist [in the HAVING clause] *only* in the same form as in those earlier column\expression lists. Since with a simple algebraic modification the noted predicate can be expressed without any arithmetic, just change the HAVING clause [as suggested by Joe] to:
coalesce(sqreq-sqfin,0)) > (lqord-lqshp)

Oddly the given query seems to include no "total of some fields" for the lack of any SUM aggregate function. Since the given query seems not to have been simplified [for reviewers], perhaps the lack of an aggregate is an oversight?

BTW, the reason the extra parentheses are a problem is that the comparison to a like-expression is done on the parsed result [a parser node?]. Thus A-B is not (A-B), because the latter has a parenthesis in the first byte whereas the former does not. A parsed expression is not "simplified", instead effectively just all of the blanks compressed out of the expression.

Regards, Chuck

As an Amazon Associate we earn from qualifying purchases.

This thread ...


Follow On AppleNews
Return to Archive home page | Return to MIDRANGE.COM home page

This mailing list archive is Copyright 1997-2024 by midrange.com and David Gibbs as a compilation work. Use of the archive is restricted to research of a business or technical nature. Any other uses are prohibited. Full details are available on our policy page. If you have questions about this, please contact [javascript protected email address].

Operating expenses for this site are earned using the Amazon Associate program and Google Adsense.