[求助]这个是什么意思

select VendorID,[164] as S164,[198] as S198
from
(select PurchaseOrderID,EmployeeID,VendorID
from Purchasing.PurchaseOrderHeader) p
pivot
(
count(PurchaseOrderID)
for EmployeeID in ([164],[198])
)
as pvt
order by VendorID