On Wed, Mar 7, 2018 at 8:20 AM, <nicolas.ro...@tiime.fr> wrote: > For example "select 1 where false" returns and empty list and this works on > at least postgres
oh ok, yes there's this also. This returns different results on MySQL vs. Postgresql: psql (9.6.7) Type "help" for help. test=# SELECT 1 in (SELECT 1 WHERE 1!=1); ?column? ---------- f (1 row) MariaDB [(none)]> SELECT 1 FROM DUAL WHERE 1!=1; Empty set (0.00 sec) MariaDB [(none)]> SELECT 1 IN (SELECT 1 FROM DUAL WHERE 1!=1); +--------------------------------------+ | 1 IN (SELECT 1 FROM DUAL WHERE 1!=1) | +--------------------------------------+ | 1 | +--------------------------------------+ 1 row in set (0.00 sec) you can see the mistake MySQL is making: MariaDB [(none)]> SELECT 5 IN (SELECT 1 FROM DUAL WHERE 1!=1); +--------------------------------------+ | 5 IN (SELECT 1 FROM DUAL WHERE 1!=1) | +--------------------------------------+ | 0 | +--------------------------------------+ 1 row in set (0.00 sec) but sure, if you can get the "empty set" expression to exist (which I don't know is possible in general) then sure. Feel free to provide tests / PRs. > (https://www.postgresql.org/message-id/20060609130037.32155.qm...@web37915.mail.mud.yahoo.com) > and mysql. > > TLDR; query producing empty lists such as "select 1 where false" may be used > as tricks to resovle the non handling of empty IN expression > > -- > SQLAlchemy - > The Python SQL Toolkit and Object Relational Mapper > > http://www.sqlalchemy.org/ > > To post example code, please provide an MCVE: Minimal, Complete, and > Verifiable Example. See http://stackoverflow.com/help/mcve for a full > description. > --- > You received this message because you are subscribed to the Google Groups > "sqlalchemy" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to sqlalchemy+unsubscr...@googlegroups.com. > To post to this group, send email to sqlalchemy@googlegroups.com. > Visit this group at https://groups.google.com/group/sqlalchemy. > For more options, visit https://groups.google.com/d/optout. -- SQLAlchemy - The Python SQL Toolkit and Object Relational Mapper http://www.sqlalchemy.org/ To post example code, please provide an MCVE: Minimal, Complete, and Verifiable Example. See http://stackoverflow.com/help/mcve for a full description. --- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To post to this group, send email to sqlalchemy@googlegroups.com. Visit this group at https://groups.google.com/group/sqlalchemy. For more options, visit https://groups.google.com/d/optout.
