sql - First n rows per group combination -


i'm trying first n rows each group combination, example

with following input first 2 rows per product-area combination, ordered date:

product  area  date        units           2015/08/07  10           2015/08/08  12           2015/08/09  15        uk    2015/08/07  13        uk    2015/08/10  11 b           2015/08/07  16 b           2015/08/08  17 b           2015/08/09  12 b        uk    2015/08/07  10 b        uk    2015/08/08  09 b        uk    2015/08/09  07

would return

product  area  date        units           2015/08/07  10           2015/08/08  12        uk    2015/08/07  13        uk    2015/08/10  11 b           2015/08/07  16 b           2015/08/08  17 b        uk    2015/08/07  10 b        uk    2015/08/08  09

i've tried:

with ordered (select product, area, date, units,                              row_number() on (partition product, area order date asc) date_rank                             mytable)                             select product, area, date, units                             ordered                              date_rank <= 2

your query returns correct results. thing see missing query order by final select:

with ordered (   select product, area, date, units     , row_number() on (partition product, area order date asc) date_rank   mytable ) select product, area, date, units ordered  date_rank <= 2 order product, area desc, date_rank

rextester demo: http://rextester.com/xoms68876

returns:

+---------+------+------------+-------+ | product | area |    date    | units | +---------+------+------------+-------+ |       |   | 2015-08-07 |    10 | |       |   | 2015-08-08 |    12 | |       | uk   | 2015-08-07 |    13 | |       | uk   | 2015-08-10 |    11 | | b       |   | 2015-08-07 |    16 | | b       |   | 2015-08-08 |    17 | | b       | uk   | 2015-08-07 |    10 | | b       | uk   | 2015-08-08 |     9 | +---------+------+------------+-------+

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