Explanation of CHAR and VARCHAR data types in SQL Server

In SQL Server, CHAR and VARCHAR are both data types used to store character data. The main difference between the two lies in how they store data:

• CHAR: The CHAR data type is fixed-length, meaning that it will always store the specified number of characters, padding any unused spaces with blank characters. For example, if you define a CHAR(10) column and insert 'hello' into it, the value will be stored as 'hello '.
• VARCHAR: The VARCHAR data type is variable-length, meaning that it will only store the actual characters entered, without any extra padding. For example, if you define a VARCHAR(10) column and insert 'hello' into it, the value will be stored as 'hello'.

Overall, CHAR is useful when you need fixed-length data and know the exact length in advance, while VARCHAR is more flexible and efficient for storing variable-length data.