Zahid Zahid - 3 months ago 5
SQL Question

Output of adding an integer and a String in SQL Server

I was asked what the following simple query would return.

Select 5 + '4'


As, 4 is string type, I expect the query to throw an error. I found I was wrong, tested it, and the result was 9. How does it return the sum?

Answer

If you mix data types such as INT and VARCHAR, SQL Server will always attempt to convert everything to the one that has the highest precedence.