[GENERAL] Some unknown error in a function

[Jasbinder Singh Bali]

Hi
Following is the script of my plpgsql function



CREATE OR REPLACE FUNCTION sp_insert_tbl_vrfy_mx(int4,text, text, inet,
text, text)
 RETURNS void AS    $$
   DECLARE
       sequence_no int4;
BEGIN
   SELECT INTO sequence_no MAX(seq_no) FROM tbl_verify_mx WHERE unmask_id =
$1;

   IF sequence_no > 1 THEN
       sequence_no = sequence_no + 1;
   ELSE
       sequence_no = 1;
   END IF;

   IF $4 =' ' THEN
       INSERT INTO tbl_verify_mx(unmask_id, seq_no, email_local,
email_domain, mail_server, mx_records )
       VALUES ($1,sequence_no,$2,$3,$5,$6) ;
   ELSE
   INSERT INTO tbl_verify_mx(unmask_id, seq_no, email_local, email_domain,
ip_address, mail_server, mx_records )
       VALUES ($1,sequence_no,$2,$3,CAST($4 as  inet), $5,$6) ;
   END IF;
END;
$$
 LANGUAGE 'plpgsql' VOLATILE;


I run this function using
select sp_insert_tbl_vrfy_mx(55,'jas','xyz.com','192.168.0.105', '
mail.xyz.com,'mxrecoredmxjdlkfjdk')
and get the following error:-

CONTEXT:  SQL statement "SELECT   $1  =' '"
PL/pgSQL function "sp_insert_tbl_vrfy_mx" line 12 at if

Don't know where I'm going wrong.
Thanks
Jas