mysql - 在 group by 中使用 Max

Question

我有以下查询，我希望它仅使用商店类别的最新日期生成结果，而不是按日期交易：

SELECT c.store,d.node_name category, x.txn_dt, x.txn_tm time, count(c.txn_id) Buyer
FROM pos_swy.5_centerstore_triptype c
join pos_swy.3_txn_itm t on c.txn_id=t.txn_id
join pos_swy.1_upc_node_map d on t.upc_id=d.upc_id
join pos_swy.3_txn_hdr x on t.txn_id=x.txn_id
group by store,txn_dt,node_name;

我尝试使用 max(x.txn_dt) 但它确实没有解决目的。

Answer 1

您可能需要订购？

    SELECT c.store,d.node_name category, max(x.txn_dt) max_date, x.txn_tm time, count(c.txn_id) Buyer
    FROM pos_swy.5_centerstore_triptype c
    join pos_swy.3_txn_itm t on c.txn_id=t.txn_id
    join pos_swy.1_upc_node_map d on t.upc_id=d.upc_id
    join pos_swy.3_txn_hdr x on t.txn_id=x.txn_id
    group by node_name
    order by max_date desc 

         -- you can change limit 1 to what ever you want to get results