Thanks. One thing to clarify, I noticed that here you used `case` without using in a context of `select`. Is this considered a shorthand within sqlalchemy?
On Fri, Dec 11, 2020 at 2:16 AM Simon King <si...@simonking.org.uk> wrote: > You can do it, but you need to use an SQL conditional rather than a > python one. In this case that would probably be a CASE expression: > > > https://docs.sqlalchemy.org/en/13/core/sqlelement.html#sqlalchemy.sql.expression.case > > I think it would look something like this: > > from sqlalchemy.sql import case > > aggr = column_property( > case([(attr_a == 'go', attr_b + attr_c)], > else_=attr_b - attr_c) > ) > > Hope that helps, > > Simon > > On Fri, Dec 11, 2020 at 9:13 AM niuji...@gmail.com <niujing...@gmail.com> > wrote: > > > > I have a mapped class: > > > > class Model(sqlalchemy.declarative_base()): > > attr_a = Column(String) > > attr_b = Column(Integer) > > attr_c = Column(Integer) > > > > aggr = column_property(attr_b + attr_c IF attr_a=='go' ELSE attr_b - > attr_c) > > > > Last line is pseoudo code that requires some conditional logic. Is such > logic allowed inside column_property? Thanks a lot! > > > > -- > > 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 view this discussion on the web visit > https://groups.google.com/d/msgid/sqlalchemy/736f0ded-e39a-47fd-a0db-8ed33057d2a3n%40googlegroups.com > . > > -- > 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 a topic in the > Google Groups "sqlalchemy" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/sqlalchemy/a_-Bqhh5wY0/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > sqlalchemy+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/sqlalchemy/CAFHwexeO2qgWeKeWPN-WH9LD8_Zch4jQRYeiB-WNbZrcMBrZFQ%40mail.gmail.com > . > -- 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 view this discussion on the web visit https://groups.google.com/d/msgid/sqlalchemy/CAOQAhNeTVkH5m-XXotNyHV_wBrb3Ev9SJnJpTYF2sRuJvxmOFA%40mail.gmail.com.
