Access a Connect By Level variable from subquery

Question

   With curr_date_details as
    select   to_date('16-dec-09', 'dd-mon-yy') as businessdate 
          ,  trunc( to_date('16-dec-09', 'dd-mon-yy'), 'iw') as bow
          ,  to_date('23-nov-09', 'dd-mon-yy')  as bop
          ,  trunc(to_date('23-nov-09', 'dd-mon-yy'),'iy')  as boy   
          ,  3 as week_nbr
          ,  3 as per_week_nbr
          ,  12 as per_nbr
   from dual
   select  --== Week Number
              case when level <= date_rec.per_week_nbr
                 then  level
                 when level = date_rec.per_week_nbr  + 1
                then 6
                when level = date_rec.per_week_nbr   + 2
                then  7
                    when level = date_rec.per_week_nbr   + 3
                then  0
            end as week_nbr
            --== Start Date
          , case when level <= date_rec.per_week_nbr
                 then  to_date('23-nov-23', 'dd-mon-rr')
                 when level = date_rec.per_week_nbr  + 1
                then  date_rec.bop
                when level = date_rec.per_week_nbr   + 2
                then  date_rec.boy  
                     when level = date_rec.per_week_nbr   + 3
                then  date_rec.boy  
            end as start_date
            --== End Date
           , case
                when level <= date_rec.per_week_nbr
                then   to_date('23-nov-23', 'dd-mon-rr')  + 6  
                  when level = date_rec.per_week_nbr  + 1
                then  date_rec.bow + 6
                 when level = date_rec.per_week_nbr  + 2
                then  date_rec.bow + 6
                        when level = date_rec.per_week_nbr   + 3
                then  date_rec.bop - 1  
             end as end_date
          --=== Dummy Column
          , case
                when level <= date_rec.per_week_nbr
                then ( select 1 + level as t  from dual)
                else  100
            end as pesky_column
      from dual mydual
      inner join curr_date_details date_rec on  date_rec.businessdate = to_date('16-dec-09', 'dd-mon-yy')
      connect by level <= date_rec.per_week_nbr  + 3gives me error:
Error at Command Line:9 Column:2
Error report:
SQL Error: ORA-01788: CONNECT BY clause required in this query block
01788. 00000 - "CONNECT BY clause required in this query block"
*Cause:   
*Action:
How can i access variable from subquery?
this question was taken from another post
Having trouble selecting from a table function

Answer 1

Hi,
Using a joiin:
WITH     connect_by_query AS
   select  --== Week Number
              case when level <= date_rec.per_week_nbr
                 then  level
                 when level = date_rec.per_week_nbr  + 1
                then 6
                when level = date_rec.per_week_nbr   + 2
                then  7
                    when level = date_rec.per_week_nbr   + 3
                then  0
            end as week_nbr
           --=== Dummy Column
       , LEVEL     AS lvl
       , per_week_nbr
      from curr_date_details date_rec
      connect by level <= date_rec.per_week_nbr  + 3
SELECT       cb.week_nbr
,       case
                when  cb.lvl <= cb.per_week_nbr
                then  NVL (sd.sales, 0)
                else  100
            end as pesky_column
FROM           connect_by_query     cb
LEFT OUTER JOIN      sample_data          sd     ON     sd.datakey = cb.lvl
ORDER BY  cb.lvl
;You could also compute week_nbr in the main query, rather than the sub-query.
Using a scalar sub-query:
WITH     connect_by_query AS
   select  --== Week Number
              case when level <= date_rec.per_week_nbr
                 then  level
                 when level = date_rec.per_week_nbr  + 1
                then 6
                when level = date_rec.per_week_nbr   + 2
                then  7
                    when level = date_rec.per_week_nbr   + 3
                then  0
            end as week_nbr
           --=== Dummy Column
       , LEVEL     AS lvl
       , per_week_nbr
      from curr_date_details date_rec
      connect by level <= date_rec.per_week_nbr  + 3
SELECT       week_nbr
,       case
                when lvl <= per_week_nbr
                then NVL ( ( select sales from sample_data where datakey = lvl)
                , 0
                else  100
            end as pesky_column
FROM       connect_by_query
ORDER BY  lvl
;Notice that the sub-query connect_by_query is the same in both cases.