无法以列形式添加逐行数据

Question

EmpID (Primary Key)  Sale Items   Paid                   
ABC                     chair      Yes                      
WXY                     chair      Under Review             
PER                    Laptop      Yes
ABC                     Chair     Yes                        

Now i want to create another table where i want to insert data Like below

Emp ID           Chair        Laptop 
ABC               2            0
WXY               1            0

My query to insert is

Select Emp Id from EMP,count(sales_item) as chair where Sales_Item = 'chair' 

it is working now how to add Laptop (3rd Column ). can you please suggest

Answer 1

You would use conditional aggregation:

Select EmpId,
       sum(case when sales_item = 'chair' then 1 else 0 end) as chairs,
       sum(case when sales_item = 'laptop' then 1 else 0 end) as laptops
from EMP
group by EmpId;

There is no reason to store this in a separate table. If you like, you can create a view. Then when you access the view, you know the data is up-to-date.

Answer 2

You could use pivot for the expected result:

DECLARE @t TABLE(
EmpID varchar(3)
,SaleItems varchar(10)
,Paid varchar(20)
)

INSERT INTO @t VALUES
('ABC', 'chair', 'Yes')
,('WXY', 'chair', 'Under Review')
,('PER', 'Laptop', 'Yes')
,('ABC', 'Chair', 'Yes')

SELECT piv.EmpID,  ISNULL(piv.chair, 0) AS chair, ISNULL(piv.Laptop, 0) AS Laptop
FROM(
  SELECT EmpID, SaleItems, 1 cnt
  FROM @t
) x
PIVOT
(
  SUM(cnt)
  FOR SaleItems IN ([chair], [Laptop])
) piv