sql - PIVOT 的 FOR 部分中的表达式

Question

我正在尝试使用 PIVOT 来获取每种产品的购买总重量，并按列中的年/月进行分割。像这样的事情:

+------------+--------+--------+--------+
| ProductKey | Jan-14 | Feb-14 | Mar-14 | Etc...
+------------+--------+--------+--------+
|         10 |   5000 |   7000 |   3000 |
|         20 |  10000 |   8000 |   6000 |
|         30 |    250 |    500 |    400 |
+------------+--------+--------+--------+

这是我第一次尝试使用 PIVOT，所以不确定这是否正确:

PIVOT
(
SUM([PO_PurchaseOrderLines].[EstimatedWeight])
FOR
LEFT(DATENAME(MONTH,[PO_Date]),3) & "-" & RIGHT(YEAR([PO_Date]),2)
IN (Jan-14, Feb-14, Mar-14, Apr-14, May-14, Jun-14, Jul-14, Aug-14, Sep-14, Oct-14, Nov-14, Dec-14, Jan-15, Feb-15, Mar-15, Apr-15, May-15, Jun-15, Jul-15, Aug-15, Sep-15, Oct-15, Nov-15, Dec-15, Jan-16, Feb-16, Mar-16, Apr-16, May-16, Jun-16, Jul-16, Aug-16, Sep-16, Oct-16, Nov-16, Dec-16, Jan-17, Feb-17, Mar-17)
) AS POPivot

运行此结果:

[Microsoft][ODBC SQL Server Driver][SQL Server]Incorrect syntax near the keyword 'LEFT'.

在 FOR 部分中使用这样的表达式是不可能的吗？还有什么不正确的吗？

Answer 1

Select *
From (
        Select ProductKey
              ,Col = format(PO_Date,'MMM-yy')
              ,EstimatedWeight
         From YourTable A
     ) A
 Pivot (sum(EstimatedWeight) For [Col] in ([Jan-14],[Feb-14],[Mar-14]) ) p