findepi commented on issue #14089: URL: https://github.com/apache/datafusion/issues/14089#issuecomment-2585678389
> I think the root cause is that SQL is largely case insensitive SQL spec seems to say that unquoted (not delimited) identifiers are equivalent to their upper-case delimited variants (ie `abc` is equivalent to `"abc"`). The equivalence relation is what's used for column resolution. Quoting SQL'16 here ``` 24) For every <identifier body> IB there is exactly one corresponding case-normal form CNF. CNF is an <identifier body> derived from IB as follows: Let n be the number of characters in IB. For i ranging from 1 (one) to n, the i-th character Mi of IB is transliterated into the corresponding character or characters of CNF as follows: Case: a) If Mi is a lower case character or a title case character for which an equivalent upper case sequence U is defined by Unicode, then let j be the number of characters in U; the next j characters of CNF are U. b) Otherwise, the next character of CNF is Mi. ``` ``` 28) A <regular identifier> and a <delimited identifier> are equivalent if the case-normal form of the <identifier body> of the <regular identifier> and the <delimited identifier body> of the <delimited identifier> (with all occurrences of <quote> replaced by <quote symbol> and all occurrences of <doublequote symbol> replaced by <double quote>), considered as the repetition of a <character string literal> that specifies a <character set specification> of SQL_IDENTIFIER and IDC, compare equally according to the comparison rules in Subclause 8.2, “<comparison predicate>” ``` However, DataFusion follows PostgreSQL variant of SQL, so my interpretation is that our intended behavior is "like in SQL spec but lower-case". -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: github-unsubscr...@datafusion.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: github-unsubscr...@datafusion.apache.org For additional commands, e-mail: github-h...@datafusion.apache.org
