Conversion failed error message when trying to join tables

Question

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I get this error message '

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

When I try to join two tables using the code below

SQL

select p.[ProductID], s.[CountryRegionCode]
FROM [Production].[Product] as p, [Sales].[SalesTerritory] as s
where s.CountryRegionCode = p.ProductID

Can anyone see why

What I have tried:

SQL

select p.[ProductID], s.[CountryRegionCode]
FROM [Production].[Product] as p, [Sales].[SalesTerritory] as s
where s.CountryRegionCode = p.ProductID

Posted 19-May-20 8:47am

yegnele46

Updated 20-May-20 19:18pm

Maciej Los

v2

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MadMyche · Answer 1 · 2020-05-19T09:03:00

The error is self-explanatory; you are trying to compare 2 values that are different data types, the first is a character string and the second is an integer.

The problem is most likely in your WHERE clause as outlined below.

SQL

SELECT p.ProductID
     , s.CountryRegionCode

FROM   Production.Product   as p
   ,   Sales.SalesTerritory as s

WHERE  s.CountryRegionCode   -- Most likely 2 letters 'US'
    =  p.ProductID           -- Most likely a number

Tony Hill · Answer 2 · 2020-05-19T09:04:00

Your problem is because the s.CountryRegionCode is a nvarchar datatype and you are trying to compare it p.ProductID which is an int.

You are trying to compare a string to a number which cannot be done, SQL attempted to implicitly convert 'US' to a int but failed because it is not a integer number.

I have to wonder how a product id actually relates to a country code which to me seems nonsensical.

Maciej Los · Answer 3 · 2020-05-19T09:09:00

The error message is quite obvious...

I suspect that
s.CountryRegionCode is type of nvarchar ('US')
p.ProductID is type of int (1, 2, ...)
which causes that these data are uncomparable!

So, to be able to join data, you have to use fields with the same type of data.

BTW: you have use Joins[^], instead of WHERE statement! For further details, please see: Visual Representation of SQL Joins[^]

ishan_shah · Answer 4 · 2020-05-20T19:19:00

Solution 4

You can also perform it like the following query :

SQL

SELECT Production.Product.ProductID
     , Sales.SalesTerritory.CountryRegionCode

FROM   Production.Product   
   ,   Sales.SalesTerritory 

WHERE  Sales.Sales.CountryRegionCode 
    =  Production.Product.ProductID

Posted 20-May-20 19:19pm

ishan_shah

Comments

Maciej Los 21-May-20 2:05am

No, he don't!
Please, read carefully an erorr message posted by OP.

Conversion failed error message when trying to join tables

4 solutions

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