Understanding SQL Data Types

SQL data types define the kind of values that can be stored in a table column. For example, if you want a column to store only integer values, you can define its data type as INT.

SQL data types can be categorized into the following groups:

• Numeric Data Types such as INT, TINYINT, BIGINT, FLOAT, REAL, etc.
• Date and Time Data Types such as DATE, TIME, DATETIME, etc.
• Character and String Data Types such as CHAR, VARCHAR, TEXT, etc.
• Unicode Character String Data Types such as NCHAR, NVARCHAR, NTEXT, etc.
• Binary Data Types such as BINARY, VARBINARY, etc.
• Special Data Types such as CLOB, BLOB, JSON, XML, GEOMETRY, etc.

In this article, you will learn about the various categories of SQL data types.

Relational Database Vendor Differences

Not all data types are supported by every relational database provider. For example:

• Oracle does not support DATETIME but provides TIMESTAMP instead.
• MySQL does not support a native CLOB type but uses TEXT equivalents.
• Microsoft SQL Server offers specific types such as MONEY and SMALLMONEY, which are not supported by other databases.

Note: Each provider has specific size limits for data types. Check the documentation of the respective provider for details.

SQL Numeric Data Types

These data types are used for numerical values:

SQL Date and Time Data Types

SQL Character and String Data Types

These data types are used for text strings:

Note: Do not use these data types for Unicode data. Use Unicode-specific data types instead.

SQL Unicode Character String Data Types

Note: These data types are not supported in MySQL databases.

SQL Binary Data Types

Special Data Types

Practical Example

CREATE TABLE ExampleTable (

ID INT PRIMARY KEY,

Name NVARCHAR(100),

Age TINYINT,

Salary DECIMAL(10, 2),

JoinDate DATE,

ProfilePicture BLOB

);

Conclusion