Part 7: Working with Date, String, and Numeric Types in SQL Server

Microsoft SQL Server Tutorial Series: Beginner to Expert

Welcome to Part 7 of our SQL Server tutorial series! In this lesson, we’ll dive into the essential data types that SQL Server offers for handling dates, strings, and numbers — the building blocks for storing and manipulating your data.

By the end of this article, you’ll understand:

How to work with date and time data types
The different string data types and their uses
Numeric types and how to choose the right one for your data
Examples of working with these data types in SQL queries

📅 Working with Date and Time Data Types

SQL Server provides several data types to store dates and times. Choosing the right one depends on the precision and storage size you need.

Data Type	Description	Storage Size	Example Format
`DATE`	Stores only date (year, month, day)	3 bytes	YYYY-MM-DD (e.g., 2025-09-09)
`TIME`	Stores time of day (hour, minute, second, fractional seconds)	3-5 bytes	HH:MM:SS[.fractional seconds]
`DATETIME`	Stores date and time with 3.33 ms precision	8 bytes	YYYY-MM-DD HH:MM:SS
`DATETIME2`	Stores date and time with higher precision	6-8 bytes	YYYY-MM-DD HH:MM:SS[.fractional seconds]
`SMALLDATETIME`	Stores date and time with less precision (1 minute)	4 bytes	YYYY-MM-DD HH:MM:00

Example: Creating a table with date and time columns

CREATE TABLE Events (
    EventID INT PRIMARY KEY,
    EventName VARCHAR(100),
    EventDate DATE,
    StartTime TIME,
    CreatedAt DATETIME2 DEFAULT SYSDATETIME()
);

📝 String Data Types in SQL Server

Strings are used to store text. SQL Server supports different string types depending on length and Unicode support:

Data Type	Description	Max Length	Use Case
`CHAR(n)`	Fixed-length non-Unicode string	1 to 8000	When string length is consistent
`VARCHAR(n)`	Variable-length non-Unicode string	1 to 8000	Most common for English or ASCII text
`VARCHAR(MAX)`	Variable-length non-Unicode string (max size)	Up to 2 GB	Very long text, e.g., descriptions, documents
`NCHAR(n)`	Fixed-length Unicode string	1 to 4000	International characters with fixed length
`NVARCHAR(n)`	Variable-length Unicode string	1 to 4000	Supports international/multilingual text
`NVARCHAR(MAX)`	Variable-length Unicode string (max size)	Up to 2 GB	Long international/multilingual text

Example: Creating a table with string columns

CREATE TABLE Users (
    UserID INT PRIMARY KEY,
    UserName VARCHAR(50),
    Email NVARCHAR(100),
    Bio VARCHAR(MAX) NULL
);

🔢 Numeric Data Types in SQL Server

Numbers in SQL Server come in various sizes and types. Here are the main numeric types:

Data Type	Description	Storage Size	Example Values
`INT`	Integer (whole number)	4 bytes	-2,147,483,648 to 2,147,483,647
`SMALLINT`	Small integer	2 bytes	-32,768 to 32,767
`TINYINT`	Very small integer	1 byte	0 to 255
`BIGINT`	Large integer	8 bytes	-9,223,372,036,854,775,808 to 9,223,372,036,854,775,807
`DECIMAL(p,s)`	Fixed precision and scale decimal number	5 to 17 bytes	e.g., DECIMAL(10,2) = 12345678.90
`FLOAT`	Approximate floating point number	4 or 8 bytes	3.14159, 2.7e10

Example: Creating a table with numeric columns

CREATE TABLE Products (
    ProductID INT PRIMARY KEY,
    ProductName VARCHAR(100),
    Price DECIMAL(10, 2),
    Quantity INT,
    Weight FLOAT
);

💡 Tips for Choosing Data Types

Use DATE if you only need the date, not time.
Choose Unicode types like NVARCHAR if your app needs to support multiple languages.
Use DECIMAL for exact numeric values like money; use FLOAT for approximate values.
Use the smallest integer type that fits your range to save space.

📋 Quick Data Types Cheat Sheet

  Dates: DATE, DATETIME, DATETIME2

  Strings: VARCHAR, NVARCHAR, CHAR, NCHAR

  Numbers: INT, SMALLINT, TINYINT, BIGINT, DECIMAL, FLOAT

🔍 Summary

Understanding SQL Server’s date, string, and numeric data types is fundamental to designing efficient databases and writing effective queries. By choosing the right data type, you optimize storage and ensure your data behaves as expected.

In the next part of this series, we’ll explore advanced SQL functions and how to manipulate data more powerfully.

Did you find this article helpful?

Feel free to leave a comment or share your questions below!

← Previous Next →

Learn Python

Menu

Working with Date, String, and Numeric Types in SQL Server - Beginner Tutorial