What's the Difference Between Varchar and Char

What's the difference between VARCHAR and CHAR?

VARCHAR is variable-length.

CHAR is fixed length.

If your content is a fixed size, you'll get better performance with CHAR.

See the MySQL page on CHAR and VARCHAR Types for a detailed explanation (be sure to also read the comments).

What's the difference between Char And VarChar

Generally, you'll want to pick varchar over char in most cases. Varchar is used when you have varying lengths of strings, making it safer, while char is good for similar lengths. Hope that helps

What is difference between char and varchar

As you said varchar is variable-length and char is fixed. But the main difference is the byte it uses.

Example.

column: username
type: char(10)

if you have data on column username which is 'test', it will use 10 bytes. and it will have space.

'test______'

Hence the varchar column will only uses the byte you use. for 'test' it will only use 4 bytes. and your data will be

'test'

THanks.

In Pro*C language, what is the difference between VARCHAR and char

The VARCHAR is a special type added by the Pro*C pre-compiler, it doesn't exist in the base C language. However, in C you can access a VARCHAR variable as a structure if I'm not mistaken.

What is the major difference between Varchar2 and char

Simple example to show the difference:

SELECT 
    '"'||CAST('abc' AS VARCHAR2(10))||'"', 
    '"'||CAST('abc' AS CHAR(10))||'"' 
FROM dual;


'"'||CAST('ABC'ASVARCHAR2(10))||'"' '"'||CAST('ABC'ASCHAR(10))||'"'
----------------------------------- -------------------------------
"abc"                               "abc       "                   
1 row selected.

The CHAR is usefull for expressions where the length of charaters is always fix, e.g. postal code for US states, for example CA, NY, FL, TX

What are the use cases for selecting CHAR over VARCHAR in SQL?

The general rule is to pick CHAR if all rows will have close to the same length. Pick VARCHAR (or NVARCHAR) when the length varies significantly. CHAR may also be a bit faster because all the rows are of the same length.

It varies by DB implementation, but generally, VARCHAR (or NVARCHAR) uses one or two more bytes of storage (for length or termination) in addition to the actual data. So (assuming you are using a one-byte character set) storing the word "FooBar"

• CHAR(6) = 6 bytes (no overhead)
• VARCHAR(100) = 8 bytes (2 bytes of overhead)
• CHAR(10) = 10 bytes (4 bytes of waste)

The bottom line is CHAR can be faster and more space-efficient for data of relatively the same length (within two characters length difference).

Note: Microsoft SQL has 2 bytes of overhead for a VARCHAR. This may vary from DB to DB, but generally, there is at least 1 byte of overhead needed to indicate length or EOL on a VARCHAR.

As was pointed out by Gaven in the comments: Things change when it comes to multi-byte characters sets, and is a is case where VARCHAR becomes a much better choice.

A note about the declared length of the VARCHAR: Because it stores the length of the actual content, then you don't waste unused length. So storing 6 characters in VARCHAR(6), VARCHAR(100), or VARCHAR(MAX) uses the same amount of storage. Read more about the differences when using VARCHAR(MAX). You declare a maximum size in VARCHAR to limit how much is stored.

In the comments AlwaysLearning pointed out that the Microsoft Transact-SQL docs seem to say the opposite. I would suggest that is an error or at least the docs are unclear.

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

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.

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