SQL Data Types with Examples

Structured Query Language (SQL) serves as the backbone for managing and manipulating relational databases. In the world of SQL, data types play a crucial role in defining the nature of data stored in tables. Choosing the right data type is essential for optimizing storage, ensuring data integrity, and improving overall database performance.

Data types define the type of data that a column can hold. They ensure that data is stored in a consistent format and provide a level of control over the kind of values that can be inserted into a column.

In the below PDF we discuss about Data Types in detail in simple language, Hope this will help in better understanding.

SQL Tutorial

Categories of SQL Data Types:

SQL data types can be broadly categorized into several groups:

1.  Numeric Data Types:
Numeric data types are used to store numeric values such as integers and floating-point numbers. Common examples include INTEGER, BIGINT, DECIMAL, and FLOAT. Choosing the appropriate numeric data type is crucial for optimizing storage and ensuring accurate representation of numerical values.

CREATE TABLE example_table (
price DECIMAL(10, 2),
quantity INT

2. Character String Data Types:
Character string data types are designed to store text values. VARCHAR, CHAR, and TEXT are commonly used types in this category. VARCHAR is variable-length, while CHAR is fixed-length. The choice between them depends on the expected length of the data.

CREATE TABLE employee (
first_name VARCHAR(50),
last_name CHAR(30),
bio TEXT

3. Date and Time Data Types:
Date and time data types are used to store temporal information. Examples include DATE, TIME, TIMESTAMP, and INTERVAL. Understanding these types is crucial for accurately representing and manipulating time-related data in your database.

event_name VARCHAR(100),
event_date DATE,
start_time TIME,
end_time TIMESTAMP

4. Boolean Data Type:
The BOOLEAN data type is used to store true or false values. It’s particularly useful for columns that represent binary choices, such as ‘active’ or ‘inactive’, ‘yes’ or ‘no’.

CREATE TABLE user_status (
user_id INT,
is_active BOOLEAN

5. Binary Data Types:
Binary data types are used to store binary data, such as images or documents. BLOB (Binary Large Object) and VARBINARY are examples of binary data types.

CREATE TABLE document (
document_id INT,
file_data BLOB

Significance of Choosing the Right Data Type:

  • Storage Optimization: Choosing appropriate data types helps optimize storage space, ensuring that tables do not consume unnecessary resources.
  • Data Integrity: Proper data types enforce data integrity by preventing incompatible data from being stored in a column.
  • Performance Enhancement:Using the correct data types contributes to faster query execution and improved overall database performance.
  • Compatibility: Ensures compatibility with other applications and systems that interact with the database.

Related Question

SQL data types are attributes that define the type of data that a column can hold in a relational database table. They specify the kind of values that can be stored in a particular column, such as integers, strings, dates, or floating-point numbers.

SQL data types can be broadly categorized into four main groups: numeric, character strings, date/time, and binary.

Numeric data types are used to store numeric values, such as integers or floating-point numbers. Examples include INT for integers and DECIMAL for fixed-point numbers.

The TIMESTAMP data type in SQL is used to store date and time values with fractional seconds precision. It is often used for recording the exact time when a record is created or modified.


A primary key is a unique identifier for a record in a table. It ensures that each row in a table can be uniquely identified and helps establish relationships between tables. A primary key column cannot contain null values, and there can be only one primary key in a table.


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