sql - 光标说它是只读的，即使我声明它是 "for update"

Question

我正在尝试更新游标内的一行。我想要做的是用 OLD_QTY 和 NEW_QTY 更新一系列记录。但是，当我尝试进行更新时，它给出了错误 The cursor is READ ONLY即使我包含了 for update of OLD_QTY, NEW_QTY在我的声明中。如果我包含 OLD_QTY 没有区别和 NEW_QTY在选择语句中。

declare @current_inv_guid uniqueidentifier
declare @last_inv_guid uniqueidentifier
declare @current_vid int
declare @last_vid int
--declare @current_new_qty money
declare @last_new_qty money
--declare @current_old_qty money

declare iaCursor cursor 
      for select INV_GUID, old_VID
          --, OLD_QTY, NEW_QTY  
          from #IA 
          order by INV_GUID, old_vid, ENTRY_NUM 
      for update --of OLD_QTY, NEW_QTY
open iaCursor
Fetch next from iaCursor into @current_inv_guid, @current_vid --, @current_old_qty, @current_new_qty

while @@fetch_status = 0
begin
    --test to see if we hit a new chain.
    if(@last_inv_guid <> @current_inv_guid or @current_vid <> @last_vid)
    begin
        set @last_new_QTY = (select #lots.QTY_RECEIVED from #lots where #lots.INV_GUID = @current_inv_guid and LOT_VID = @current_vid)
        set @last_inv_guid = @current_inv_guid
        set @last_vid = @current_vid    
    end

    --update the current link in the chain
    update #ia
        set OLD_QTY = @last_new_QTY,
            NEW_QTY = @last_new_QTY + QTY_CHANGE,
            @last_new_QTY = @last_new_QTY + QTY_CHANGE
        where current of iaCursor

    --get the next link
    fetch next from iaCursor into @current_inv_guid, @current_vid --, @current_old_qty, @current_new_qty
end 

close iaCursor
deallocate iaCursor

Answer 1

放一个 order by在 select使光标只读。