Conversion failed when converting the ****** value '******' to data type ******

Question

I\'m getting this error from SQL Server on SSMS 17 while running a giant query:

Conversion failed when converting the ****** value \'******\' to data type

Answer 1

My error was also: Conversion failed when converting the ****** value '******' to data type ******.

My issue ended up being in my join, which was joining a varchar(50) field on an int field.

SELECT TOP (10) Product.Name, ProductDetails.Price
FROM Product
--the ProductDetails.Product field is a varchar field that contains 
--a string of the ProductID which is an int in the Product table
FULL JOIN Product.ProductID = ProductDetails.Product 

I corrected this by casting the int field to a varchar

FULL JOIN CAST(Product.ProductID as varchar(50)) = ProductDetails.Product

P.S. I went back and later changed to a Left outer join which made more since for our business logic. Also I did not test this code, it is modified for illustration purposes.

Details on reproducing: Sometimes the query would work fine. I found I personally had issues when I had TWO string comparisons in my WHERE clause e.g.

WHERE field like '%' + @var + '%'
OR field2 like '%' + @var2 + '%'

If I had just one comparison, it seemed to work fine.