從另一列 sql / presto 計算百分比

Question

我有這張桌子

month_year  shopid  payment_method   count
Jul-19      3lokpn99    CC           115
Jul-19      3lokpn99    PAYPALL      1
Jul-19      6jyhikmm    CC           180
Jul-19      6jyhikmm    PAYPALL      7
Aug-19      3lokpn99    CC           108
Aug-19      3lokpn99    PAYPALL      4
Aug-19      6jyhikmm    CC           114
Aug-19      6jyhikmm    PAYPALL      3

我正在尋找的是計算當月每種付款方式的百分比。 想要的結果是這樣的

month_year  shopid  payment_method   count   %
Jul-19      3lokpn99    CC           115    99.14
Jul-19      3lokpn99    PAYPALL      1      0.86
Jul-19      6jyhikmm    CC           180    96.26
Jul-19      6jyhikmm    PAYPALL      7      3.74
Aug-19      3lokpn99    CC           108    96.43
Aug-19      3lokpn99    PAYPALL      4      3.57
Aug-19      6jyhikmm    CC           114    97.4
Aug-19      6jyhikmm    PAYPALL      3      2.56

Answer 1

有不同的方法可能

• 使用 Window 功能
• 自加入聚合（如 Wojciech 的回答中所述）

Window 函數方法具有額外的優勢，即源數據只讀一次。

SELECT month_year, shopid, payment_method, count,
    100e0 * count / sum(count) OVER (
        PARTITION BY month_year, shopid
        RANGE BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING)
        AS "%"
FROM ...

（在 Presto 318 上測試）

請參閱 Presto Window Function 文檔https://trino.io/docs/current/functions/window.ZCD235FDC8B5261Z文檔

Answer 2

您可以通過查詢來實現此結果：

SELECT s.*, ROUND(s.count / ss.count_summed * 100,2) AS `%`
FROM stack s
JOIN (SELECT s.month_year, s.shopid, SUM(s.count) AS count_summed FROM stack s GROUP BY s.month_year, s.shopid) ss ON ss.month_year = s.month_year AND ss.shopid = s.shopid;