What is Signed and Unsigned Integers

• In MySQL, "signed" and "unsigned" refer to the two possible variations of integer data types, such as INT, BIGINT, SMALLINT, and TINYINT. These variations determine whether the integer can store both positive and negative numbers or only non-negative (positive) numbers. 

Let's dive into the details of signed and unsigned integers:
Signed Integers:

• Signed integers can represent both positive and negative numbers.

• The range of values for signed integers is divided symmetrically around zero.

• For example, a signed 32-bit INT can store values from -2,147,483,648 to 2,147,483,647.

• The most significant bit (MSB) of a signed integer represents the sign (positive or negative). The MSB is 0 for positive numbers and 1 for negative numbers.

• The remaining bits represent the magnitude of the number.

Unsigned Integers:

• Unsigned integers can only store non-negative (positive) numbers.

• The range of values for unsigned integers starts from zero and goes up to the maximum representable value for the given data type.

• For example, an unsigned 32-bit INT can store values from 0 to 4,294,967,295.

• All bits in an unsigned integer are used to represent the magnitude of the number. There is no bit reserved for representing the sign because unsigned numbers are always positive.

When to use Signed vs. Unsigned Integers:

• Use Signed Integers: When you need to store values that can be both positive and negative, choose the signed integer data types (e.g., INT, BIGINT, SMALLINT, TINYINT). This is suitable for cases where the range of values includes negative numbers or where you need to represent quantities with a signed representation.

• Use Unsigned Integers: When you know that the values you need to store are always non-negative (positive) and you want to maximize the range of values, choose the unsigned integer data types (e.g., INT UNSIGNED, BIGINT UNSIGNED, SMALLINT UNSIGNED, TINYINT UNSIGNED). Unsigned integers are often used for cases like representing quantities, counts, or identifiers that are guaranteed to be positive.

• The choice between signed and unsigned integers depends on the specific requirements of your application and the range of values you expect to handle. By selecting the appropriate variant, you can ensure data accuracy and optimize storage space.