SQL compatibility reminder: MySQL vs PostgreSQL
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From: Hitoshi Harada on 8 Mar 2010 12:14 2010/3/9 Jaime Casanova <jcasanov(a)systemguards.com.ec>: > On Mon, Mar 8, 2010 at 4:17 AM, Pierre C <lists(a)peufeu.com> wrote: >> >>> My opinion is that PostgreSQL should accept any MySQL syntax and return >>> warnings. I believe that we should access even innodb syntax and turn it >>> immediately into PostgreSQL tables. This would allow people with no >>> interest in SQL to migrate from MySQL to PostgreSQL without any harm. >> >> A solution would be a SQL proxy (a la pgpool) with query rewriting. >> > > This sounds like a better idea... Could parser & rewriter hook be another solution here? I'm completely against the wrong GROUP BY syntax from MySQL, but it is also true that SQL is only an interface. -- Hitoshi Harada -- Sent via pgsql-hackers mailing list (pgsql-hackers(a)postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
From: Robert Haas on 8 Mar 2010 12:18 On Mon, Mar 8, 2010 at 12:10 PM, David Fetter <david(a)fetter.org> wrote: > On Mon, Mar 08, 2010 at 11:58:20AM -0500, Jaime Casanova wrote: >> On Mon, Mar 8, 2010 at 4:17 AM, Pierre C <lists(a)peufeu.com> wrote: >> > >> >> My opinion is that PostgreSQL should accept any MySQL syntax and >> >> return warnings. I believe that we should access even innodb >> >> syntax and turn it immediately into PostgreSQL tables. This would >> >> allow people with no interest in SQL to migrate from MySQL to >> >> PostgreSQL without any harm. >> > >> > A solution would be a SQL proxy (a la pgpool) with query >> > rewriting. >> >> This sounds like a better idea... > > Aside from that little "halting problem" issue, it sounds wonderful. > You do know that SQL is Turing-complete, right? That seems largely irrelevant to the problem at hand. It's not impossible to do syntactic transformations from one Turing-complete langauge to another; if it were, there could be no such thing as a compiler. ....Robert -- Sent via pgsql-hackers mailing list (pgsql-hackers(a)postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
From: David Fetter on 8 Mar 2010 12:43 On Mon, Mar 08, 2010 at 12:18:31PM -0500, Robert Haas wrote: > On Mon, Mar 8, 2010 at 12:10 PM, David Fetter <david(a)fetter.org> wrote: > > On Mon, Mar 08, 2010 at 11:58:20AM -0500, Jaime Casanova wrote: > >> On Mon, Mar 8, 2010 at 4:17 AM, Pierre C <lists(a)peufeu.com> wrote: > >> > > >> >> My opinion is that PostgreSQL should accept any MySQL syntax > >> >> and return warnings. I believe that we should access even > >> >> innodb syntax and turn it immediately into PostgreSQL tables. > >> >> This would allow people with no interest in SQL to migrate > >> >> from MySQL to PostgreSQL without any harm. > >> > > >> > A solution would be a SQL proxy (a la pgpool) with query > >> > rewriting. > >> > >> This sounds like a better idea... > > > > Aside from that little "halting problem" issue, it sounds > > wonderful. You do know that SQL is Turing-complete, right? > > That seems largely irrelevant to the problem at hand. It's not > impossible to do syntactic transformations from one Turing-complete > langauge to another; if it were, there could be no such thing as a > compiler. MySQL's SQL isn't Turing complete. Cheers, David. -- David Fetter <david(a)fetter.org> http://fetter.org/ Phone: +1 415 235 3778 AIM: dfetter666 Yahoo!: dfetter Skype: davidfetter XMPP: david.fetter(a)gmail.com iCal: webcal://www.tripit.com/feed/ical/people/david74/tripit.ics Remember to vote! Consider donating to Postgres: http://www.postgresql.org/about/donate -- Sent via pgsql-hackers mailing list (pgsql-hackers(a)postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
From: Robert Haas on 8 Mar 2010 13:04 On Mon, Mar 8, 2010 at 12:43 PM, David Fetter <david(a)fetter.org> wrote: > On Mon, Mar 08, 2010 at 12:18:31PM -0500, Robert Haas wrote: >> On Mon, Mar 8, 2010 at 12:10 PM, David Fetter <david(a)fetter.org> wrote: >> > On Mon, Mar 08, 2010 at 11:58:20AM -0500, Jaime Casanova wrote: >> >> On Mon, Mar 8, 2010 at 4:17 AM, Pierre C <lists(a)peufeu.com> wrote: >> >> > >> >> >> My opinion is that PostgreSQL should accept any MySQL syntax >> >> >> and return warnings. I believe that we should access even >> >> >> innodb syntax and turn it immediately into PostgreSQL tables. >> >> >> This would allow people with no interest in SQL to migrate >> >> >> from MySQL to PostgreSQL without any harm. >> >> > >> >> > A solution would be a SQL proxy (a la pgpool) with query >> >> > rewriting. >> >> >> >> This sounds like a better idea... >> > >> > Aside from that little "halting problem" issue, it sounds >> > wonderful. You do know that SQL is Turing-complete, right? >> >> That seems largely irrelevant to the problem at hand. It's not >> impossible to do syntactic transformations from one Turing-complete >> langauge to another; if it were, there could be no such thing as a >> compiler. > > MySQL's SQL isn't Turing complete. It still doesn't matter. Turing-completeness does not preclude syntax transformation. Non-Turing completeness, even less so. ....Robert -- Sent via pgsql-hackers mailing list (pgsql-hackers(a)postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
From: Andrew Dunstan on 8 Mar 2010 13:07
Robert Haas wrote: >> You do know that SQL is Turing-complete, right? >> > > That seems largely irrelevant to the problem at hand. It's not > impossible to do syntactic transformations from one Turing-complete > langauge to another; if it were, there could be no such thing as a > compiler. > > > If we were engaged in an academic exercise this might be interesting. But we aren't. The fact that one can do something is not an argument for actually doing it. cheers andrew -- Sent via pgsql-hackers mailing list (pgsql-hackers(a)postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers |