Re: [BUGS] Bug #513: union all changes char(3) column definition

Thread added to TODO.detail.

> Tom Lane writes:
> 
> > The argument here is about how much intelligence it's reasonable to
> > expect the system to have.  It's very clearly not feasible to derive
> > a length limit automagically in every case.  How hard should we try?
> 
> I would like to know what Proprietary database #1 does with
> 
> CREATE TABLE one ( a bit(6) );
> INSERT INTO one VALUES ( b'101101' );
> CREATE TABLE two ( b bit(4) );
> INSERT INTO two VALUES ( b'0110' );
> CREATE TABLE three AS SELECT a FROM one UNION SELECT b FROM two;
> 
> According to SQL92, clause 9.3, the result type of the union is bit(6).
> However, it's not possible to store a bit(4) value into a bit(6) field.
> Our current solution, "bit(<nothing>)" is even worse because it has no
> real semantics at all (but you can store bit(<anything>) in it,
> interestingly).
> 
> -- 
> Peter Eisentraut   peter_e@gmx.net
> 
> 

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