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Scalar

In SQL, a scalar type is a type that holds a single value as opposed to composite types that hold multiple values. In simpler terms, scalar types represent a single unit of data.

Some common examples of scalar types in SQL include:

  • Integers (INT)
  • Floating-point numbers (FLOAT)
  • Strings (VARCHAR, CHAR)
  • Date and Time (DATE, TIME)
  • Boolean (BOOL)

Examples​

Here is how you can define different scalar types in SQL:

Integers​

An integer can be defined using the INT type. Here is an example of how to declare an integer:

CREATE TABLE Employees (
    EmployeeID INT,
    FirstName VARCHAR(50),
    LastName VARCHAR(50)
);

Floating-Point Numbers​

Floating-point numbers can be defined using the FLOAT or REAL type. Here is an example of how to declare a floating-point number:

CREATE TABLE Products (
    ProductID INT,
    Price FLOAT
);

Strings​

Strings can be defined using the CHAR, VARCHAR, or TEXT type. Here is an example of how to declare a string:

CREATE TABLE Employees (
    EmployeeID INT,
    FirstName VARCHAR(50), 
    LastName VARCHAR(50) 
);

Date and Time​

The DATE, TIME or DATETIME type can be used to define dates and times:

CREATE TABLE Orders (
    OrderID INT,
    OrderDate DATE
);

Boolean​

Booleans can be declared using the BOOL or BOOLEAN type. They hold either TRUE or FALSE.

CREATE TABLE Employees (
    EmployeeID INT,
    IsActive BOOL
);

Remember, the way these types are declared might slightly differ based on the SQL dialect you are using. It's crucial to refer to the specific documentation of the SQL flavor you're working with for the precise syntax and behavior.