Re: Functional index and string concatenation - Mailing list pgsql-sql

Edmund Bacon <ebacon@onesystem.com> writes:
> On Mon, 2004-03-08 at 08:19, Daniel Henrique Alves Lima wrote:
>> Is there a way to create a "functional index" over a string 
>> concatenation of two columns ?

> test=# create index str_idx on strtable( textcat(str1, str2) );

As of 7.4 you can do it more directly:

create index str_idx on strtable( (str1 || str2) );

The disadvantage of the textcat() locution is that the planner will only
match it up to queries that also say textcat().
        regards, tom lane