Question

I have three tables such as TableA, TableB and TableC. I want to update one column in TableA from the column value in TableC. But there is no direct relationship b/w TableA and TableC. But TableB has relationship with both the tables A and C. How can I update? The structure of the tables are given below:

  TableA:                  TableB:               TableC:
 ----------               -----------           ----------
  ItemID                   ID                     ID
  Name                     ItemDetailID           D1
  Quantity                 TotalQty               D2
  Rate                     TotalAmount            D3 
  ItemDetailID             TotalWeight            Quantity

Here I want to update TableA Column “Quantity” with TableC column value “Quantity”.
I used Update select statement using two tables. But not like this. How to do? Please give suggestions…

Answer 1

Something like:

Update a
set a.Quantity = c.Quantity
from TableA a
join TableB b on b.ItemDetailId = a.ItemDetailId
join TableC c on c.ID = b.ID