Click here to Skip to main content
11,410,750 members (64,549 online)

s_ohama asked:

Open original thread
Someone please help me.

I'm not good in English, so my explanation might be ununderstandable a little.
Sorry about that.

Main question is
"Would MAX() return zero record?"

Following is my situation.

My application -coded in c#- connects Postgres with Npgsql.

I've understood MAX() as function which never returns zero record*.
However, it retruned zero record when application issued a SQL which gets MAX() by ExecuteScalar.

Officials say that ExecuteScalar returns
"The first column of the first row in the result set, or a null reference (Nothing in Visual Basic) if the result set is empty."
And in my case, returned object is Null.
If so, I think MAX() would return zero record in a certain case.

Then, go back to the question
"Would MAX() return zero record?"
If the answer is Yes,
"when is it??"
If the answer is No,
"why was the object Null??"

I'm having trouble reproducing this phenomenon for a long time.
Please give me your hand.


*object is primarykey.
Tags: C#, PostgreSQL

Preview



When answering a question please:
  1. Read the question carefully.
  2. Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
  3. If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Let's work to help developers, not make them feel stupid.
Please note that all posts will be submitted under the The Code Project Open License (CPOL).



Advertise | Privacy | Mobile
Web03 | 2.8.150414.5 | Last Updated 26 Mar 2009
Copyright © CodeProject, 1999-2015
All Rights Reserved. Terms of Service
Layout: fixed | fluid

CodeProject, 503-250 Ferrand Drive Toronto Ontario, M3C 3G8 Canada +1 416-849-8900 x 100