MySQL ZEROFILL: When and Why Should You Use It?

MySQL Zerofill: Benefits and Usage

MySQL's ZEROFILL attribute for INT data types offers several advantages in certain scenarios.

When applied to an integer column, ZEROFILL specifies that its displayed value should be padded with zeros up to a pre-defined width. This behavior is distinct from regular integers, which automatically truncate values exceeding the display width.

Benefits of ZEROFILL:

• Visual consistency: ZEROFILL ensures that values of varying lengths are displayed with a consistent width, making it easier to align and compare them.
• Improved readability: Zero padding improves the readability of large numbers, especially when presented in tabular formats.
• Leading zeroes preservation: Unlike regular integers, ZEROFILL preserves leading zeroes, which can be useful when displaying serial numbers or identification codes.

Usage:

ZEROFILL can be used in conjunction with the display width modifier. For example, the following statement defines a column that will display 8-digit integer values with zero padding:

`id` INT UNSIGNED ZEROFILL NOT NULL 

Example:

Consider the following SQL query:

CREATE TABLE yourtable (x INT(8) ZEROFILL NOT NULL, y INT(8) NOT NULL);
INSERT INTO yourtable (x,y) VALUES
(1, 1),
(12, 12),
(123, 123),
(123456789, 123456789);
SELECT x, y FROM yourtable;

Result:

        x          y
 00000001          1
 00000012         12
 00000123        123
123456789  123456789

In this example, the x column displays integer values with zero padding, while the y column displays the same values without padding. This demonstrates the visual difference and improved readability offered by ZEROFILL.

Note that ZEROFILL also implies UNSIGNED, meaning that negative values cannot be stored in these columns.

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