difference between char and varchar in sql

Difference between CHAR and VARCHAR in SQL

Introduction

SQL is a standard language used for managing various relational databases. In SQL, CHAR and VARCHAR are two data types used to store character strings. Although both are used to store strings, there is a substantial difference between these two data types. Here’s what you need to know about CHAR and VARCHAR.

CHAR

CHAR is a fixed-length character data type in SQL. In this data type, you can specify the maximum length of the string that can be stored in the column. CHAR columns are padded with spaces, so if you specify a length of 10, even if the string is only six characters long, four spaces will be added to the end of the string to fill the column’s capacity.

For example, if you have a CHAR column with a length of 10 and you insert “Hello” into the column, the values will be stored like this: “Hello_____” (where “_” represents a space).

VARCHAR

VARCHAR is a variable-length character data type in SQL, which means it can store any number of characters up to a maximum limit. Unlike CHAR columns, VARCHAR columns do not store trailing spaces, so if you insert “Hello” into a VARCHAR column of length 10, only “Hello” will be stored, making it a much more efficient storage method.

Comparing the differences between CHAR and VARCHAR

The key difference between CHAR and VARCHAR data types in SQL is that CHAR columns are fixed-length, while VARCHAR columns are variable length.

CHAR columns take up more space than VARCHAR columns because they are padded with spaces. This is because when working with CHAR columns, the database management system needs to know how much space to allocate to each column.

VARCHAR is more space-efficient when compared to CHAR, as it only consumes the amount of space required to store the string. As a result, VARCHAR is a good choice when working with large databases where space is an issue.

Conclusion

In summary, CHAR and VARCHAR are two commonly used data types in SQL for storing character strings. The primary difference between the two is that CHAR columns take up more storage space, while VARCHAR is more space-efficient. CHAR is best used when working with fixed-length strings, while VARCHAR is ideal for storing variable-length character strings. Understanding the differences between these two data types is crucial when building and managing databases, as it helps prevent data and column sizing issues.

Table difference between char and varchar in sql

Difference	Char	Varchar
Data Type	Fixed-length non-Unicode character data	Variable-length non-Unicode character data
Storage Requirement	The storage size is always equal to the maximum defined length of the field. Unused spaces are padded with spaces.	The storage size is equal to the actual data length plus two bytes.
Maximum Length	Maximum size is between 1 to 8,000 characters.	Maximum size is between 1 to 8,000 characters.
Default Length	The length is always specified, and if the field is shorter, it is padded with spaces.	The length is not specified, and the data is stored as it is.
Performance	Fixed-length fields are faster to process due to their fixed size.	Variable-length fields can take longer to process due to their variable size, but they can save space.
Usage	Char should be used when storing data that is of a fixed length, such as phone numbers, SSN.	Varchar should be used when storing data that is variable in length, such as names, addresses.