Sql 基于列值有条件地选择行

从该表中，对于每个范围_ID，我需要使用以下条件选择行： 如果存在除ID字段外具有相同列的行，则仅选择具有FLAG_LINE=1的行；如果存在相同的行，但其中没有一行包含FLAG_LINE=1列，则选择所有行，基于此，查询应返回以下结果：

ID  RANGE_ID            START_DATE    END_DATE    BAND_TYPE           FLAG_LINE
3     1               01/03/2013    31/03/2013          R                   1
4     1               01/03/2013    31/03/2013          R                   0
5     2               01/03/2013    31/03/2013          R                   1
6     2               01/03/2013    31/03/2013          R                   0
7     3               01/03/2013    31/03/2013          R                   0
8     3               01/03/2013    31/03/2013          N                   0

我试着分块进行：即为每个范围运行类似的程序：

ID  RANGE_ID          START_DATE    END_DATE      BAND_TYPE           FLAG_LINE
3     1               01/03/2013    31/03/2013          R                   1
5     2               01/03/2013    31/03/2013          R                   1
7     3               01/03/2013    31/03/2013          R                   0
8     3               01/03/2013    31/03/2013          N                   0

对于每个范围使用此方法，我填充一个临时表，并在最后返回结果，但这不是很灵活，是否有其他方法可以实现

谢谢

像这样试试

begin
  for x in ( select count(*) cnt
               from dual 
              where exists (
                select 1 FROM myTable 
                WHERE RANGE_ID = 1 AND FLAG_LINE = 1) )
  loop
        if ( x.cnt = 1 ) 
        then
           dbms_output.put_line('flag line exists');
           --insert the line with FLAG_LINE = 1 into temp table for this range
        else 
           dbms_output.put_line('does not exist');
           --insert the lines into temp table for this range
        end if;
  end loop;
end;

像这样试试

begin
  for x in ( select count(*) cnt
               from dual 
              where exists (
                select 1 FROM myTable 
                WHERE RANGE_ID = 1 AND FLAG_LINE = 1) )
  loop
        if ( x.cnt = 1 ) 
        then
           dbms_output.put_line('flag line exists');
           --insert the line with FLAG_LINE = 1 into temp table for this range
        else 
           dbms_output.put_line('does not exist');
           --insert the lines into temp table for this range
        end if;
  end loop;
end;

试试这个

Select * from tablename where flag=1 
union 
(Select * from tablename a where  (Select count(*) from tablename b 
where a.Range_id=b.RANGE_ID  and b.flag=1)<1)

试试这个

Select * from tablename where flag=1 
union 
(Select * from tablename a where  (Select count(*) from tablename b 
where a.Range_id=b.RANGE_ID  and b.flag=1)<1)

---

这里有另一种方法可以得到你想要的结果

select * from myTable
 where flag_line = 1
       or
       (range_id, start_date, end_date, band_type) in (
                  select range_id, start_date, end_date, band_type
                    from myTable
                group by range_id, start_date, end_date, band_type
                  having max(flag_line) = 0)

---

这里有另一种方法可以得到你想要的结果

select * from myTable
 where flag_line = 1
       or
       (range_id, start_date, end_date, band_type) in (
                  select range_id, start_date, end_date, band_type
                    from myTable
                group by range_id, start_date, end_date, band_type
                  having max(flag_line) = 0)