Question

what is the difference between char , varchar and nvarchar in sql?

Answer 1

Char DataType

Char datatype which is used to store fixed length of characters. Suppose if we declared char(50) it will allocates memory for 50 characters. Once we declare char(50) and insert only 10 characters of word then only 10 characters of memory will be used and other 40 characters of memory will be wasted.

varchar DataType

Varchar means variable characters and it is used to store non-unicode characters. It will allocate the memory based on number characters inserted. Suppose if we declared varchar(50) it will allocates memory of 0 characters at the time of declaration. Once we declare varchar(50) and insert only 10 characters of word it will allocate memory for only 10 characters.

nvarchar DataType

nvarchar datatype same as varchar datatype but only difference nvarchar is used to store Unicode characters and it allows you to store multiple languages in database. nvarchar datatype will take twice as much space to store extended set of characters as required by other languages.

Answer 2

nchar and nvarchar can store Unicode characters.
char and varchar cannot store Unicode characters.
char and nchar are fixed-length which will reserve storage space for number of characters you specify even if you don't use up all that space.
varchar and nvarchar are variable-length which will only use up spaces for the characters you store. It will not reserve storage like char or nchar.

Answer 3

char(n)Fixed length non unicode character data with length of n bytes.n must be a value from 1 through 8,000.

varchar(n)variable length non unicode character data with length of n bytes.

nvarchar(n)variable length unicode character data of n characters. n must be a value from 1 through 4,000.