What is the difference between char nchar varchar and nvarchar in SQL Server

Question

What is meant by nvarchar   What is the difference between char  nchar  varchar  and nvarchar in SQL Server

User · Answer

All the answers so far indicate that varchar is single byte  nvarchar  is double byte  The first part of this actually depends on collation as illustrated below   DECLARE  T TABLE   C1 VARCHAR 20  COLLATE Chinese Traditional Stroke Order 100 CS AS KS WS  C2 NVARCHAR 20 COLLATE  Chinese Traditional Stroke Order 100 CS AS KS WS    INSERT INTO  T      VALUES  N          N                        N abc  N abc     SELECT C1         C2         LEN C1         AS  LEN C1           DATALENGTH C1  AS  DATALENGTH C1           LEN C2         AS  LEN C2           DATALENGTH C2  AS  DATALENGTH C2   FROM    T     Returns    Note that the   and   characters were still not represented in the VARCHAR version and were silently replaced with     There are actually still no Chinese characters that can be reprsented by a single byte in that collation  The only single byte characters are the typical western ASCII set   Because of this it is possible for an insert from a nvarchar X  column to a varchar X  column to fail with a truncation error  where X denotes a number that is the same in both instances    SQL Server 2012 adds SC  Supplementary Character  collations that support UTF-16  In these collations a single nvarchar character may take 2 or 4 bytes

User · Answer

nchar is fixed-length and can hold unicode characters  it uses two bytes storage per character  varchar is of variable length and cannot hold unicode characters  it uses one byte storage per character

User · Answer

Just to clear up    or sum up      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    nchar and nvarchar will take up twice as much storage space  so it may be wise to use them only if you need Unicode support

User · Answer

nchar and char pretty much operate in exactly the same way as each other  as do nvarchar and varchar  The only difference between them is that nchar nvarchar store Unicode characters  essential if you require the use of extended character sets  whilst varchar does not   Because Unicode characters require more storage  nchar nvarchar fields take up twice as much space  so for example in earlier versions of SQL Server the maximum size of an nvarchar field is 4000    This question is a duplicate of this one

User · Answer

nchar is fixed-length and can hold unicode characters  it uses two bytes storage per character  varchar is of variable length and cannot hold unicode characters  it uses one byte storage per character

User · Answer

NVARCHAR can store Unicode characters and takes 2 bytes per character

User · Answer

nchar requires more space than nvarchar   eg   A nchar 100  will always store 100 characters even if you only enter 5  the remaining 95 chars will be padded with spaces  Storing 5 characters in a nvarchar 100   will save 5 characters

User · Answer

char  fixed-length character data with a maximum length of 8000 characters  nchar  fixed-length unicode data with a maximum length of 4000 characters  Char   8 bit length NChar   16 bit length

User · Answer

My attempt to summarize and correct the existing answers   First  char and nchar will always use a fixed amount of storage space  even when the string to be stored is smaller than the available space  whereas varchar and nvarchar will use only as much storage space as is needed to store that string  plus two bytes of overhead  presumably to store the string length   So remember   var  means  variable   as in variable space   The second major point to understand is that  nchar and nvarchar store strings using exactly two bytes per character  whereas char and varchar use an encoding determined by the collation code page  which will usually be exactly one byte per character  though there are exceptions  see below   By using two bytes per character  a very wide range of characters can be stored  so the basic thing to remember here is that nchar and nvarchar tend to be a much better choice when you want internationalization support  which you probably do   Now for some some finer points   First  nchar and nvarchar columns always store data using UCS-2  This means that exactly two bytes per character will be used  and any Unicode character in the Basic Multilingual Plane  BMP  can be stored by an nchar or nvarchar field  However  it is not the case that any Unicode character can be stored  For example  according to Wikipedia  the code points for Egyptian hieroglyphs fall outside of the BMP  There are  therefore  Unicode strings that can be represented in UTF-8 and other true Unicode encodings that cannot be stored in a SQL Server nchar or nvarchar field  and strings written in Egyptian hieroglyphs would be among them  Fortunately your users probably don t write in that script  but it s something to keep in mind   Another confusing but interesting point that other posters have highlighted is that char and varchar fields may use two bytes per character for certain characters if the collation code page requires it   Martin Smith gives an excellent example in which he shows how Chinese Traditional Stroke Order 100 CS AS KS WS exhibits this behavior  Check it out    UPDATE  As of SQL Server 2012  there are finally code pages for UTF-16  for example Latin1 General 100 CI AS SC  which can truly cover the entire Unicode range

User · Answer

nchar is fixed-length and can hold unicode characters  it uses two bytes storage per character  varchar is of variable length and cannot hold unicode characters  it uses one byte storage per character

User · Answer

nchar and char pretty much operate in exactly the same way as each other  as do nvarchar and varchar  The only difference between them is that nchar nvarchar store Unicode characters  essential if you require the use of extended character sets  whilst varchar does not   Because Unicode characters require more storage  nchar nvarchar fields take up twice as much space  so for example in earlier versions of SQL Server the maximum size of an nvarchar field is 4000    This question is a duplicate of this one

User · Answer

NVARCHAR can store Unicode characters and takes 2 bytes per character

User · Answer

nchar requires more space than nvarchar   eg   A nchar 100  will always store 100 characters even if you only enter 5  the remaining 95 chars will be padded with spaces  Storing 5 characters in a nvarchar 100   will save 5 characters

User · Answer

The differences are     n var char stores unicode while  var char just stores single-byte characters   n char requires a fixed number of characters of the exact length while  n varchar accepts a variable number of characters up to and including the defined length    Another difference is length  Both nchar and nvarchar can be up to 4 000 characters long  And char and varchar can be up to 8000 characters long  But for SQL Server you can also use a  n varchar max  which can handle up to 2 147 483 648 characters   Two gigabytes  a signed 4-byte integer

User · Answer

nchar requires more space than nvarchar   eg   A nchar 100  will always store 100 characters even if you only enter 5  the remaining 95 chars will be padded with spaces  Storing 5 characters in a nvarchar 100   will save 5 characters

User · Answer

nchar  n      national character    Fixed-length Unicode string data  n defines the string length and must be a value from 1 through 4 000  The storage size is two times n bytes      nvarchar   n   max    national character varying     Variable-length Unicode string data   n defines the string length and can be a value from 1 through 4 000  max indicates that the maximum storage size is 2 31-1 bytes  2 GB   The storage size  in bytes  is two times the actual length of data entered   2 bytes     char   n    character    Fixed-length  non-Unicode string data  n defines the string length and must be a value from 1 through 8 000  The storage size is n bytes      varchar   n   max    character varying    Variable-length  non-Unicode string data  n defines the string length and can be a value from 1 through 8 000  max indicates that the maximum storage size is 2 31-1 bytes  2 GB   The storage size is the actual length of the data entered   2 bytes

User · Answer

nchar is fixed-length and can hold unicode characters  it uses two bytes storage per character  varchar is of variable length and cannot hold unicode characters  it uses one byte storage per character

User · Answer

nchar and char pretty much operate in exactly the same way as each other  as do nvarchar and varchar  The only difference between them is that nchar nvarchar store Unicode characters  essential if you require the use of extended character sets  whilst varchar does not   Because Unicode characters require more storage  nchar nvarchar fields take up twice as much space  so for example in earlier versions of SQL Server the maximum size of an nvarchar field is 4000    This question is a duplicate of this one

User · Answer

nchar 10  is a fixed-length Unicode string of length 10  nvarchar 10  is a variable-length Unicode string with a maximum length of 10  Typically  you would use the former if all data values are 10 characters and the latter if the lengths vary

User · Answer

nchar and char pretty much operate in exactly the same way as each other  as do nvarchar and varchar  The only difference between them is that nchar nvarchar store Unicode characters  essential if you require the use of extended character sets  whilst varchar does not   Because Unicode characters require more storage  nchar nvarchar fields take up twice as much space  so for example in earlier versions of SQL Server the maximum size of an nvarchar field is 4000    This question is a duplicate of this one

User · Answer

nchar 10  is a fixed-length Unicode string of length 10  nvarchar 10  is a variable-length Unicode string with a maximum length of 10  Typically  you would use the former if all data values are 10 characters and the latter if the lengths vary

User · Answer

NVARCHAR can store Unicode characters and takes 2 bytes per character

User · Answer

Just to clear up    or sum up      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    nchar and nvarchar will take up twice as much storage space  so it may be wise to use them only if you need Unicode support

User · Answer

NVARCHAR can store Unicode characters and takes 2 bytes per character

User · Answer

nchar 10  is a fixed-length Unicode string of length 10  nvarchar 10  is a variable-length Unicode string with a maximum length of 10  Typically  you would use the former if all data values are 10 characters and the latter if the lengths vary

User · Answer

Just to clear up    or sum up      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    nchar and nvarchar will take up twice as much storage space  so it may be wise to use them only if you need Unicode support

User · Answer

The differences are     n var char stores unicode while  var char just stores single-byte characters   n char requires a fixed number of characters of the exact length while  n varchar accepts a variable number of characters up to and including the defined length    Another difference is length  Both nchar and nvarchar can be up to 4 000 characters long  And char and varchar can be up to 8000 characters long  But for SQL Server you can also use a  n varchar max  which can handle up to 2 147 483 648 characters   Two gigabytes  a signed 4-byte integer

User · Answer

Just to add something more  nchar - adds trailing spaces to the data  nvarchar - does not add trailing spaces to the data   So  if you are going to filter your dataset by an  nchar  field  you may want to use RTRIM to remove the spaces  E g  nchar 10  field called BRAND stores the word NIKE  It adds 6 spaces to the right of the word  So  when filtering  the expression should read  RTRIM Fields BRAND Value     NIKE   Hope this helps someone out there because I was struggling with it for a bit just now

User · Answer

My attempt to summarize and correct the existing answers   First  char and nchar will always use a fixed amount of storage space  even when the string to be stored is smaller than the available space  whereas varchar and nvarchar will use only as much storage space as is needed to store that string  plus two bytes of overhead  presumably to store the string length   So remember   var  means  variable   as in variable space   The second major point to understand is that  nchar and nvarchar store strings using exactly two bytes per character  whereas char and varchar use an encoding determined by the collation code page  which will usually be exactly one byte per character  though there are exceptions  see below   By using two bytes per character  a very wide range of characters can be stored  so the basic thing to remember here is that nchar and nvarchar tend to be a much better choice when you want internationalization support  which you probably do   Now for some some finer points   First  nchar and nvarchar columns always store data using UCS-2  This means that exactly two bytes per character will be used  and any Unicode character in the Basic Multilingual Plane  BMP  can be stored by an nchar or nvarchar field  However  it is not the case that any Unicode character can be stored  For example  according to Wikipedia  the code points for Egyptian hieroglyphs fall outside of the BMP  There are  therefore  Unicode strings that can be represented in UTF-8 and other true Unicode encodings that cannot be stored in a SQL Server nchar or nvarchar field  and strings written in Egyptian hieroglyphs would be among them  Fortunately your users probably don t write in that script  but it s something to keep in mind   Another confusing but interesting point that other posters have highlighted is that char and varchar fields may use two bytes per character for certain characters if the collation code page requires it   Martin Smith gives an excellent example in which he shows how Chinese Traditional Stroke Order 100 CS AS KS WS exhibits this behavior  Check it out    UPDATE  As of SQL Server 2012  there are finally code pages for UTF-16  for example Latin1 General 100 CI AS SC  which can truly cover the entire Unicode range

User · Answer

nchar 10  is a fixed-length Unicode string of length 10  nvarchar 10  is a variable-length Unicode string with a maximum length of 10  Typically  you would use the former if all data values are 10 characters and the latter if the lengths vary

User · Answer

char  fixed-length character data with a maximum length of 8000 characters  nchar  fixed-length unicode data with a maximum length of 4000 characters  Char   8 bit length NChar   16 bit length

User · Answer

All the answers so far indicate that varchar is single byte  nvarchar  is double byte  The first part of this actually depends on collation as illustrated below   DECLARE  T TABLE   C1 VARCHAR 20  COLLATE Chinese Traditional Stroke Order 100 CS AS KS WS  C2 NVARCHAR 20 COLLATE  Chinese Traditional Stroke Order 100 CS AS KS WS    INSERT INTO  T      VALUES  N          N                        N abc  N abc     SELECT C1         C2         LEN C1         AS  LEN C1           DATALENGTH C1  AS  DATALENGTH C1           LEN C2         AS  LEN C2           DATALENGTH C2  AS  DATALENGTH C2   FROM    T     Returns    Note that the   and   characters were still not represented in the VARCHAR version and were silently replaced with     There are actually still no Chinese characters that can be reprsented by a single byte in that collation  The only single byte characters are the typical western ASCII set   Because of this it is possible for an insert from a nvarchar X  column to a varchar X  column to fail with a truncation error  where X denotes a number that is the same in both instances    SQL Server 2012 adds SC  Supplementary Character  collations that support UTF-16  In these collations a single nvarchar character may take 2 or 4 bytes

User · Answer

Just to clear up    or sum up      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    nchar and nvarchar will take up twice as much storage space  so it may be wise to use them only if you need Unicode support

User · Answer

nchar requires more space than nvarchar   eg   A nchar 100  will always store 100 characters even if you only enter 5  the remaining 95 chars will be padded with spaces  Storing 5 characters in a nvarchar 100   will save 5 characters

User · Answer

nchar  n      national character    Fixed-length Unicode string data  n defines the string length and must be a value from 1 through 4 000  The storage size is two times n bytes      nvarchar   n   max    national character varying     Variable-length Unicode string data   n defines the string length and can be a value from 1 through 4 000  max indicates that the maximum storage size is 2 31-1 bytes  2 GB   The storage size  in bytes  is two times the actual length of data entered   2 bytes     char   n    character    Fixed-length  non-Unicode string data  n defines the string length and must be a value from 1 through 8 000  The storage size is n bytes      varchar   n   max    character varying    Variable-length  non-Unicode string data  n defines the string length and can be a value from 1 through 8 000  max indicates that the maximum storage size is 2 31-1 bytes  2 GB   The storage size is the actual length of the data entered   2 bytes

User · Answer

Just to add something more  nchar - adds trailing spaces to the data  nvarchar - does not add trailing spaces to the data   So  if you are going to filter your dataset by an  nchar  field  you may want to use RTRIM to remove the spaces  E g  nchar 10  field called BRAND stores the word NIKE  It adds 6 spaces to the right of the word  So  when filtering  the expression should read  RTRIM Fields BRAND Value     NIKE   Hope this helps someone out there because I was struggling with it for a bit just now

[sql-server] What is the difference between char, nchar, varchar, and nvarchar in SQL Server?

Examples related to sql-server

Examples related to varchar