Problems with '||' concatenation operator.

Dear All,

I'm trying to get the concatenation operator (||) to work with different
character variables (i.e. varchar and bpchar)... and failing.

consider the following:

create table experiment (
chromosome varchar(2), // that for chromosomes 1-22 and X and Y
arm char(1) // can only be one of 'q' or 'p'
);

insert into experiment values ('22','q');
insert into experiment values ('17','p');

select * from experiment;
chromosome|arm
----------+---
22|q
17|p
(2 rows)

I want to select a field as the concatenation of the chromosome and the arm...

cgh=> select chromosome || arm as locus from experiment;
ERROR: There is more than one possible operator '||' for types 'varchar'
and 'b
pchar'
You will have to retype this query using an explicit cast
cgh=>

tried casting one as the other:

cgh=> select chromosome::bpchar || arm as locus from experiment;
ERROR: There is more than one possible operator '||' for types 'varchar'
and 'b
pchar'
You will have to retype this query using an explicit cast

or

cgh=> select chromosome || arm::varchar as locus from experiment;
ERROR: There is more than one possible operator '||' for types 'varchar'
and 'b
pchar'
You will have to retype this query using an explicit cast
cgh=>

tried converting both to text (in desperation!):

cgh=> select chromosome::text || arm::text as locus from experiment;
ERROR: There is more than one possible operator '||' for types 'varchar'
and 'b
pchar'
You will have to retype this query using an explicit cast
cgh=>

Any suggestions on how to get the concatenation to work?
Also, I'm hoping to eventually concatenate an int4 field to the other two
so, having solved the above problem, how would I tackle that one?

Regards,

S.

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| Stuart Rison | Ludwig Institute for Cancer Research |
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