Re: how to concatenate in PostgreSQL

On 3/24/12, Andreas Kretschmer <akretschmer@spamfence.net> wrote:
> Rehan Saleem <pk_rehan@yahoo.com> wrote:
>
>> hi ,
>> how can we concatinate these lines and execute sql command
>>
>>        set sql = 'select user,username, firstname '
>>       set sql += ' lastname, cardno from table1 where userid=' + 5
>
> sql = sql || ' bla fasel';
>
> || is the concat - Operator.
>
>
>
> Andreas
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You may want to ensure that none of variables to be concatenated is
NULL, else the end result will be NULL.
"coalesce" function provides means to provide an substitute value for
a variable that may be NULL.

Allan.