Talk:Null (SQL)

message: Why has this page been written? In SQL, null has exactly the same meaning / behavior it has in ALL programming languages. The only thing that COULD (but not in my opinion) justify this page, would have been some discussion about UNKNOWN pseudo-value. But there is nothing like that, so this page is misleading for someone who doesn't know that null is.  — Preceding unsigned comment added by 151.21.9.214 (talk) 14:37, 5 October 2011 (UTC)
thread_title:  I think this is duplicate page 

message: CJ Date says the SQL 3VL logic is none of those usually studied. John Grant says it's Kleene's K3. Thalheim and Schewe say it's Łukasiewicz L3. They can't all be right. What's more amusing is that they disagree about such basic facts. Tijfo098 (talk) 19:44, 7 November 2012 (UTC)
replies: text: Actually, this mystery has been solved, cf  p. 9. Basically it's both K3 and L3 because they differ only in their table for implication, but SQL has no such operand. And in this sense, SQL's is also an incompletely specified logic. So all of them (Date, Grant and Thalheim & Schewe) are correct! Tijfo098 (talk) 16:25, 8 November 2012 (UTC)
thread_title:  Amazing and amusing contradictions  

message: The catch is that in implementations which distinguish boolean NULL from Unknown, like in that of Microsoft, an expression like TRUE OR NULL (e.g. "(1 <> 2) OR NULL") fails the type check, so you can't speak of its result, because it's a parsing error. Unless someone can produce a reliable source for this so-called inconsistency, I'll delete the claim. Tijfo098 (talk) 15:31, 8 November 2012 (UTC)
thread_title:  Claimed inconsistency of boolean variables 

message: The chapter "When two nulls are equal: ..." seems to be outdated. Actually it reads: "Because SQL:2003 defines all Null markers as being unequal to one another...". The content of the chapter is not incorrect, but the actual standard uses more elegant expressions - with a slightly different semantic. SQL:2011 defines in 4.1.5 Properties of distinct the rule "Two null values are not distinct.". Is this only a problem of linguistic representation within the wiki-article or is it a progress in the SQL standard, which is not reflected by the article? As far as I know, the semantic of GROUP BY and other related language elements hasn't changed from 2003 to 2011. --Kelti (talk) 19:57, 11 May 2014 (UTC)
thread_title:  Nulls are Equal ? 

message: The section “Analysis of SQL Null missing-value semantics”
seems to provide private Nonsens:
The “groundbreaking work of T. Imielinski and W. Lipski (1984)” 
was and is completely unknown to the database community.
The proposition
“and if  is its lifting to a construct intended to represent missing information”
has no truth value, thus no content.  — Preceding unsigned comment added by 94.219.112.101 (talk) 17:47, 13 May 2015 (UTC)
thread_title:  The part  

message: I would suggest that "null" is used for the general concept and "NULL" the SQL implementation.  While a lot of the SQL I write uses Null or null, it seems that listing a table with a null field will show NULL.  This makes it the "natural" representation in SQL.  Unless anyone has a better idea?  All the best: Rich Farmbrough, 21:39, 21 November 2016 (UTC)
replies: text: The ISO SQL specification (ISO/IEC 9075-2:2016(E)) uses upper case for the NULL keyword, and lower case for the <I>null value</I>, but never Null. Fjerdingen (talk) 20:46, 8 June 2017 (UTC)
thread_title: NULL, Null, or null