What about: SELECT A, B, COALESCE(C, 'some value here') FROM MyTable
Greetings. Walter. On Tue, Oct 10, 2017 at 2:56 PM, 'Daniel Miller' dmil...@amfes.com [firebird-support] <firebird-support@yahoogroups.com> wrote: > > > I don't think you could express it in the SELECT directly (someone else > will probably build a statement refuting that) but you could do: > > SELECT r.RDB$FIELD_NAME FROM RDB$RELATION_FIELDS r where > r.RDB$RELATION_NAME=<your table name here> > > and then process that result set to build your appropriate SELECT for > the target table. So I suppose you could build a statement with a > quantity of derived sets using IIF and WHERE EXISTS - the question is do > you need to express this as single SELECT, or can you accomplish your > goal either via your calling program or a stored procedure? > -- > Daniel > > On 10/9/2017 1:36:20 AM, "Elmar Haneke el...@haneke.de > [firebird-support]" <firebird-support@yahoogroups.com> wrote: > > > > >>Is there a way to include a column in a SELECT but substitute a value > >>if > >>it doesn't? I need my code to work with different versions of my db > >>schema. > >> > >>eg I want to SELECT A, B, C, ... but C might not exist. > >> > >>SELECT * would work of course, except it will fetch a bunch of columns > >>I > >>don't need. > > > >You can read the list of fields available in advance and modify your > >query ommitting missing columns. > > > > > >Elmar > > > > > > > >------------------------------------ > >Posted by: Elmar Haneke <el...@haneke.de> > >------------------------------------ > > > >++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > > > >Visit http://www.firebirdsql.org and click the Documentation item > >on the main (top) menu. Try FAQ and other links from the left-side > >menu there. > > > >Also search the knowledgebases at > >http://www.ibphoenix.com/resources/documents/ > > > >++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > >------------------------------------ > > > >Yahoo Groups Links > > > > > > > > >
