What are the key differences between BigInt, MediumInt, and Int data types in MySQL?

Understanding the Difference Between BigInt, MediumInt, and Int in MySQL

When dealing with numerical data in MySQL, developers often encounter terms like BigInt, MediumInt, and Int. While these data types all handle integer values, they possess distinct characteristics that affect their usage and storage.

BigInt(20) vs Int(20)

Contrary to intuitive assumptions, the numbers in parentheses (20 in this case) do not indicate a size limit or the number of digits that can be stored. Instead, they specify the display width, which affects the formatting of values in certain contexts.

Storage and Value Range

The fundamental difference between BigInt and Int lies in their storage size. BigInt occupies eight bytes, allowing it to store numbers in the range of -9223372036854775808 to 9223372036854775807 (approximately ±2⁶³). In contrast, Int, being a four-byte data type, can hold values between -2147483648 to 2147483647 (approximately ±2³¹).

Therefore, BigInt should be used when dealing with large numbers that may exceed the capacity of Int. This is especially common in financial, scientific, or statistical applications.

Display Width and ZEROFILL

The display width specified in BigInt(20) or Int(20) comes into play when using the ZEROFILL attribute. It defines the number of digits that will be padded with zeros to align the value on display. For instance, if an Int(20) ZEROFILL column contains the value 1234, it will be displayed as "00000000000000001234."

Choosing the Right Data Type

When selecting which data type to use for numerical data, it's crucial to consider the following factors:

• Expected value range: Use BigInt for large numbers or values that could potentially exceed the limits of Int.
• Display requirements: Use a specific display width if desired zero-padding or alignment.
• Database performance: BigInt requires more storage space and may impact performance in data-intensive applications.

Remember, the choice of data type not only affects the storage and retrieval of data but can also have implications for query performance and data integrity.

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