Re: ANSI SQL, CASE expression Conformance F262, F263 any info
От | Pavel Stehule |
---|---|
Тема | Re: ANSI SQL, CASE expression Conformance F262, F263 any info |
Дата | |
Msg-id | BAY20-F146B9BD5A448F02383684CF93B0@phx.gbl обсуждение исходный текст |
Ответ на | Re: ANSI SQL, CASE expression Conformance F262, F263 any info (Tom Lane <tgl@sss.pgh.pa.us>) |
Список | pgsql-hackers |
>"Pavel Stehule" <pavel.stehule@hotmail.com> writes: > > I can't find any information of syntax for ANSI Conformance F262, F263. >Has > > somebody any information about this points: Extended CASE expression, >comma > > separated predicates in simple case expression > >There are no such feature IDs listed in either SQL99 or SQL2003. What >are you reading? > > regards, tom lane First, I looked http://www.postgresql.org/docs/8.1/interactive/unsupported-features-sql-standard.html I don't found any information on internet - only BNF syntax for SQL 2003. http://savage.net.au/SQL/sql-2003-2.bnf.html#xref-CASE SQL2003 has little bit different syntax for CASE. example: BETWEEN <between> := <row value> between_part2 <between_part2> := [NOT] BETWEEN [ASYMMETRIC|SYMMETRIC] <row value> AND <row value> --------------------------- <simple_case> := CASE <row value> <simple_when_clause> [<else_clause>] END <simple_when_clause := WHEN <when_operand> THEN <result> <when_operand> := <row value> | <between_part2> | .... so I can: SELECT CASE EXTRACT(minute FROM when_col) WHEN BETWEEN 0 AND 14 THEN 0 WHEN BETWEEN 15 AND 29 THEN 15 WHEN BETWEEN30 AND 44 THEN 30 ELSE 45 END this is extended CASE expression propably F262. About F263 I don't found any indicies. Maybe it's SELECT CASE col WHEN 1,3,5,7,9,11 THEN false ELSE END I looked into parser. F262 is usefull, but I am not sure if can be implemented. It's need refactoring gram.y or duplicate code for CASE, and maybe others - is possible share one operand in more expressions? I see others ANSI or NON ANSI enhancing as much usefull: window function or autonomous transaction. Regards Pavel Stehule _________________________________________________________________ Chcete sdilet sve obrazky a hudbu s prateli? http://messenger.msn.cz/
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