I am trying to move all the data from one column in an Excel sheet into a SQL Server database table using SQL Server Management Studio. The data in the table covers different OS versions by year, and some of them contain letters, such as 2008R2.

When I tried to move the data into the table, I get an error saying that Null types are not allowed in that column. But when I changed the column to allow Null types, anything that contained a letter or a non-numeric character was designated as Null. The attribute in question is stored in its original table as a float, but I want it to be varchar in my table.

I ran a basic T-SQL INSERT INTO command like this:

INSERT INTO Instance
    SELECT Version, OS, SpotPrice, ContractPrice 
    FROM dbo.Data$;

All numeric entries were put into the table, and entries containing non-numeric characters were input as Null.