Question

我有两个表说X和表Y.X有order_id，offer_id。 order_id可以有多个offer_id。现在我想以这样的方式将数据插入到Y（id，offer_id）中，对于offer_id的每个不同组合，我想要一个id。例如。

表X：

order_id offer_id
2581681     24
2581681     23
2581936     23
2581936     24
2582001     23
2582001     24
2595298     24
2595298     14
2596247     24
2596247     14
2596268     14
2596268     24
1911365     1
1922052     1
1922803     1
1923501     1
1924074     1
1924963     1

表Y应该是这样的：

id     offer_id
1         23
1         24
2         14
2         24
3          1

Answer 1

如果您想要任意数量的优惠，那么问题就很难了。这接近你想要的：

select (@rn := @rn + 1) id, offers
from (select group_concat(distinct x.offer_id order by x.offer_id) as offers
      from tableX x
      group by x.order_id
     ) xx cross join
     (select @rn := 0) var
group by offers;

这会将商品放在以逗号分隔的列表中的单行上。如果你真的需要它们在不同的行上，我会建立在这个：

select id, substring_index(substring_index(offers, ',', n.n), ',', -1) as offer
from (select (@rn := @rn + 1) id, offers
      from (select group_concat(distinct x.offer_id order by x.offer_id) as offers,
                   count(distinct x.offer_id) as numoffers
            from tableX x
            group by x.order_id
           ) xx cross join
           (select @rn := 0) var
      group by offers
     ) o join
     (select 1 as n union all select 2 as n union all select 3 as n union all select 4 as n
     ) n
     on n.n <= numoffers;

当然，n子查询需要至少包含订单的最大商品数量。

按order_id分组并在mysql中将id分配给offer_id

1 个答案: