varchar vs char
var
The length can be changed (extra 2 bytes used for length records)
n
support unicode (2 bytes per word)
| Types | Length | Unicode | Memory |
|---|---|---|---|
| char | Fixed-length | No | n bytes |
| varchar | Variable-length | No | n+2 bytes |
| nchar | Fixed-Length | Yes | n*2 bytes |
| nvarchar | Variable-Length | Yes | n*2+2 bytes |