CHARINDEX ( expressionToFind , expressionToSearch [ , start_location ] )  

       pos2:=strpos(SUBSTRING(string,pos1+1), ' ');
        IF(pos2>0)
        THEN
            pos2:=pos2 + pos1+1;
        END IF;
-- ....

CREATE OR REPLACE FUNCTION charindex(text, text, integer) 
RETURNS integer AS $$ 
SELECT CASE WHEN strpos(substr($2, $3+1), $1) = 0 
THEN 0 ELSE strpos(substr($2, $3+1), $1) + $3 END; 
$$ LANGUAGE SQL IMMUTABLE RETURNS NULL ON NULL INPUT;