Regarding sql query

I have the below sql query to insert the records from a tab开发者_开发百科le. The problem is when there is no records for select query i still want an record with the sequence number,null,'3' value inserted. Nothing get's inserted when there is no record found for select query. how can i do it?

insert into test_details(seqnbr,trepid,type)
select '&seqid'
      ,REP_ID
      ,'3'
  FROM ref_details
 WHERE REP_ID >13;

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One way would be

insert into test_details(seqnbr,trpid,type)
select '&seqid',rep_id,'3' from ref_details where rep_id>13
union all select '&seqid',null,'3'
from dual where not exists(
select 1 from ref_details where rep_id>13)

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Oracle 9i+:

To fill in gaps, you need to create a list of sequencial values:

INSERT INTO TEST_DETAILS
  (seqnbr, trpid, type)
 SELECT '&seqid', rd.rep_id, '3'
     FROM (SELECT LEVEL + 13
             FROM DUAL
       CONNECT BY LEVEL <= 13) x
LEFT JOIN REF_DETAILS rd ON rd.rep_id = x.level
                        AND rd.rep_id > 13

...then LEFT JOIN to the table that can have gaps.