Please go read the Transact-SQL manual.

I just showed you above that you concatenate strings in SQL using the '+' operator:  select "A" + ICD_9 ...

You are at a point where you don't yet understand SQL - I strongly suggest that until you understand SQL you leave perl and DBI out of it, and write the queries that you want to execute in a text editor and run them using isql.exe or some other tool that connects directly to the database. This will give you direct feedback on what you are doing.

Are you inserting a NEW row in the ICD_9_Disease_Types table, or are you updating an existing row?

From the code above I am guessing that you are updating an existing row, in which case you need to know the relationship between the two tables.

Michael