SQL trunc/group/order by dates (day/month/quarter/year) with sum skip dates with no data

Question

I involved in project where I need to build histogram by dates. Before me this done in Java code by tons of SQL queries to DB for each rectangles (date subregions).

I tr

Answer 1

My production code based on local guru advises and @Ben technique:

-- generate sequence 1..N:
SELECT level FROM dual CONNECT BY level <= 4;

-- generates days:
select to_date('01-01-2012','DD-MM-YYYY') + level - 1
  from dual
connect by level <= to_date('31-12-2012','DD-MM-YYYY') - to_date('01-01-2012','DD-MM-YYYY') + 1;

with dates as (
  select (to_date('01-01-2012','DD-MM-YYYY') + level - 1) as daterange
    from dual
    connect by level <= to_date('31-12-2012','DD-MM-YYYY') - to_date('01-01-2012','DD-MM-YYYY') + 1
  ) select sum(tbl.cnt) as summ, trunc(dates.daterange, 'DDD')
      from dates
           left outer join DATA_TBL tbl
        on trunc(tbl.inc_date, 'DDD') = trunc(dates.daterange, 'DDD')
      group by trunc(dates.daterange, 'DDD')
      order by trunc(dates.daterange, 'DDD');

-- generates months:
select ADD_MONTHS(to_date('01-01-2012','DD-MM-YYYY'), level - 1)
  from dual
connect by level <= months_between(to_date('31-12-2012','DD-MM-YYYY'), to_date('01-01-2012','DD-MM-YYYY')) + 1;

with dates as (
  select add_months(to_date('01-01-2012','DD-MM-YYYY'), level-1) as daterange
    from dual
    connect by level <= months_between(to_date('31-12-2012','DD-MM-YYYY'), to_date('01-01-2012','DD-MM-YYYY')) + 1
  ) select sum(tbl.cnt) as summ, trunc(dates.daterange, 'MM')
      from dates
           left outer join DATA_TBL tbl
        on trunc(tbl.inc_date, 'MM') = trunc(dates.daterange, 'MM')
      group by trunc(dates.daterange, 'MM')
      order by trunc(dates.daterange, 'MM');

-- generates quarters:
select ADD_MONTHS(to_date('01-01-2012','DD-MM-YYYY'), (level-1)*3)
  from dual
  connect by level <= months_between(to_date('31-12-2012','DD-MM-YYYY'), to_date('01-01-2012','DD-MM-YYYY'))/3 + 1;

with dates as (
  select add_months(to_date('01-01-2012','DD-MM-YYYY'), (level-1)*3) as daterange
    from dual
    connect by level <= months_between(to_date('31-12-2012','DD-MM-YYYY'), to_date('01-01-2012','DD-MM-YYYY'))/3 + 1
  ) select sum(tbl.cnt) as summ, trunc(dates.daterange, 'Q')
      from dates
           left outer join DATA_TBL tbl
        on trunc(tbl.inc_date, 'Q') = trunc(dates.daterange, 'Q')
      group by trunc(dates.daterange, 'Q')
      order by trunc(dates.daterange, 'Q');

-- generates years:
select add_months(to_date('01-01-2007','DD-MM-YYYY'), (level-1)*12)
  from dual
  connect by level <= months_between(to_date('31-01-2012','DD-MM-YYYY'), to_date('01-01-2007','DD-MM-YYYY'))/12 + 1;

with dates as (
  select add_months(to_date('01-01-2007','DD-MM-YYYY'), (level-1)*12) as daterange
    from dual
    connect by level <= months_between(to_date('31-01-2012','DD-MM-YYYY'), to_date('01-01-2007','DD-MM-YYYY'))/12 + 1
  ) select sum(tbl.cnt) as summ, trunc(dates.daterange, 'YYYY')
      from dates
           left outer join DATA_TBL tbl
        on trunc(tbl.inc_date, 'YYYY') = trunc(dates.daterange, 'YYYY')
      group by trunc(dates.daterange, 'YYYY')
      order by trunc(dates.daterange, 'YYYY');

But connect by level is hack according to:

• http://www.sqlsnippets.com/en/topic-11821.html (Gotchas. To Use PRIOR or Not to Use PRIOR, That is the Question)