按周分组，获取一周的第一天，按工作日旋转

Question

我需要进行查询，以显示每个客户每周（按周分组）订购的每个项目/单元组合的数量，同时显示一周的第一天，还显示该周每天的订购量（按工作日的枢轴） ）。 到目前为止，我有这个，但是我不确定如何按周分组。

SELECT customer_name, item_code, item_desc,  unit, delivery_date, [Monday], [Tuesday], [Wednesday], [Thursday], [Friday], [Saturday], [Sunday]
FROM (
    SELECT customer_name, item_code , item_desc , unit, delivery_date, DATENAME(dw, delivery_date) AS DayWeek, qty
    FROM order_items oi inner join orders on localID = local_order_id
    ) AS ordersItems
    pivot (
        SUM(qty) FOR DayWeek IN ([Monday], [Tuesday], [Wednesday], [Thursday], [Friday], [Saturday], [Sunday])
    ) AS pvt

Answer 1

以下查询按客户/项目/单位/周＃组合分组。 它返回订单总数以及按星期几细分的订单数。 CASE语句与SUM函数一起使用，以获取一周中每一天的订单总数

编辑 ：修改查询以按周开始日期分组（而不是以前的第＃周）

SELECT customer_name, item_code, item_desc, unit, 
CASE SIGN(7-(DATEPART(dw, action)+2))
  WHEN -1 THEN CAST(DATEADD(dd, 7-(DATEPART(dw, action)+2), action) AS DATE)
  WHEN 0 THEN CAST(action AS DATE)
  WHEN 1 THEN CAST(DATEADD(dd, -(DATEPART(dw, action)+2), action) AS DATE)
END Week_Starting_Friday
SUM(qty) Total_Orders, 
SUM(
    CASE DATENAME(dw, delivery_date) WHEN 'Monday' THEN qty ELSE 0 END
) [Monday],
SUM(
    CASE DATENAME(dw, delivery_date) WHEN 'Tuesday' THEN qty ELSE 0 END
) [Tuesday],
SUM(
    CASE DATENAME(dw, delivery_date) WHEN 'Wednesday' THEN qty ELSE 0 END
) [Wednesday],
SUM(
    CASE DATENAME(dw, delivery_date) WHEN 'Thursday' THEN qty ELSE 0 END
) [Thursday],
SUM(
    CASE DATENAME(dw, delivery_date) WHEN 'Friday' THEN qty ELSE 0 END
) [Friday],
SUM(
    CASE DATENAME(dw, delivery_date) WHEN 'Saturday' THEN qty ELSE 0 END
) [Saturday],
SUM(
    CASE DATENAME(dw, delivery_date) WHEN 'Sunday' THEN qty ELSE 0 END
) [Sunday]
FROM order_items oi inner join orders on localID = local_order_id
GROUP BY customer_name, item_code, item_desc, unit, 
CASE SIGN(7-(DATEPART(dw, action)+2))
  WHEN -1 THEN CAST(DATEADD(dd, 7-(DATEPART(dw, action)+2), action) AS DATE)
  WHEN 0 THEN CAST(action AS DATE)
  WHEN 1 THEN CAST(DATEADD(dd, -(DATEPART(dw, action)+2), action) AS DATE)
END
ORDER BY 5, customer_name, item_code, item_desc, unit;

参考文献 ：

1. MSDN上的CASE声明
2. MSDN上的DATENAME