How can I converting the nvarchar value to data type int

Question

WITH FirstQuery AS (
  select i.id, o.[name]  from Item i
  LEFT OUTER JOIN sys.objects o on o.[name]='I' + cast(i.id as nvarchar(20))
  where o.name is not null
)
select PriceListItem.ProductExternalId,
       FQ.Id,   [PriceListItem].[ProductExternalDesc]
from FirstQuery FQ
     inner join [Product] on Product.ItemId = FQ.name
                         and Product.InstanceId = FQ.ID
     inner join [PriceListItem]  on Product.ID = PriceListItem.ProductId;

It has an error:

Conversion failed when converting the nvarchar value 'I451' to data type int.

Answer 1

So... It looks like you are trying to join on Product.ItemID (int) = FQ.name (varchar) .

Why did you think that would work?

Sample data may help people figure out what you are trying to do and how you should accomplish it.

Answer 2

If you still want to join on these two columns and want it to not match when it's an invalid int, maybe do it the other way around. Cast Product.ItemID to a varchar:

inner join [Product] on cast(Product.ItemID as varchar) = FQ.name