Best practice for concatenation in SQL Server?

Question

My row has a NVARCHAR value in a certain column. I want to be able to concatenate onto this value eg, if the row stores "Hello," I want to be able to run a db.Execute command to keep the "Hello" and tag on " my name is Earl" so that "Hello, my name is Earl" is stored in the row.

What is the best practice for doing this?

db.Execute("UPDATE table SET description = description + '--@0 likes this' WHERE id = @1",user, id);

This doesnt accept the parameters and actually inserts @0and @1 into the database. Why is this ?

Answer 1

Just a guess, but try moving @0 out of the single quotes:

db.Execute(@"
    UPDATE table 
    SET description = description + @0 + ' likes this' 
    WHERE id = @1",user, id); 

Answer 2

If you have a table myTable with a message column you want to concat and the row id is 5 ...

UPDATE myTable
SET message = concat(message, N' my name is earl')
WHERE id = 5;  -- some where condition that identifies row(s)