SQL。 如何根据一列中的值将具有相同ID的两条记录合并为一行

Question

SQL Server 2012: how to combine two records with the same ID (TransportOrder) into one line based on value's in a column (PalletType)?

Example: order 678 has two lines with 1 europallet en 3 BetweenEuropallet. So de order takes only 1 TransportEuropalletPlace.

The output should be in the case of order 678, one line, telling there is total 4 europallets (sum 1 + 3 from two lines) and 1 TransportEuropalletPlace (SUM 1 + 0)

How to achieve this with SQL query?

Original output:

TransportOrder   PalletType            Quantity    TransportEuropalletPlace
--------------------------------------------------------------------------
      123        Minipallet               1                0.5
      345        Europallet               1                1
      678        Europallet               1                1
      678        BetweenEuropallet        3                0
      900        Europallet               2                2

Output needed for order 678:

TransportOrder   PalletType    Quantity    TransportEuropalletPlace 
--------------------------------------------------------------------------
     123         Minipallet       1              0.5 
     345         Europallet       1              1 
     678         Europallet       4              1 
     900         Europallet       2              2 

Answer 1

This should get you started:

SELECT
    TransportOrder,
    SUM(ISNULL(Europallet,0) + ISNULL(BetweenEuropallet, 0)) as 'Pallets'
FROM Table_Name
GROUP BY TransportOrder

Answer 2

You should group by the column TransportOrder , as in:

select
  transportorder,
  max(pallettype) as pallettype,
  sum(quantity) as quantity,
  sum(transporteuropalletplace) as transporteuropalletplace
from my_table
group by transportorder