Understanding SQL Server Data Types (And When to Use Them)


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One of the first things someone new to SQL Server wants to know is what data types are available and when they should be used. In this blog, I’ll teach you everything about how SQL Server organizes data with its different storage engines and talk about some best practices for making sure you’re using your data type correctly in queries.

The “sql server data types with examples” is a blog post that provides an overview of SQL Server Data Types. It also includes some examples of when to use each type.

Understanding SQL Server Data Types (And When to Use Them)

Understanding how SQL saves data is crucial whether you’re a database administrator (DBA) or just wear the hat of “database man.” How should a string, a number, a file, or a date be stored? Understanding SQL Server data types may help you answer these problems.

In this article, you’ll learn about SQL Server data types, how to differentiate between them, and how to choose the optimal type for your SQL data.

What are the different types of data in SQL Server?

To comprehend SQL data kinds, you must first comprehend SQL data. You may store a wide variety of data with SQL, including words (strings), numbers (integers and floats), dates and times, and even whole files. SQL can’t store this data in the same manner since it’s inefficient.

For efficiency and performance reasons, each kind of data has its own distinct properties and should be treated appropriately.

Although each SQL data type has its own set of characteristics for storing various sorts of data, they all share a few characteristics:

  • Characters are the “foundation” of all SQL data types. Characters are used to represent a single data entity of any sort. A character might be a text, an integer number, or even a date in a DateTime data type, for example. The word “moses,” for example, comprises five characters, whereas the numeric data type “123.456” has seven, including the decimal point.
  • Size – The amount of memory utilized by the data type to specify the size of the data. Bytes are always used to measure size, with one byte equaling one symbol or character. When saved as an English letter, SQL stores the letter ‘a’ as one byte, two bytes when stored as a European or Middle Eastern letter, and three bytes when stored as an Asian letter.
  • In any data type, length refers to the number of characters. A character in a string of letters, a byte in binary code, or the number one in an integer might all be considered characters.

Tips for Choosing a SQL Data Type in General

All of the major SQL data types are covered in this article. You’ll learn about their distinct qualities as well as the types of data they may hold. But, before you go too detailed, keep the two most crucial considerations in mind: storage and performance.

  • Storage – When you create a data type, you automatically allocate a specific amount of space. As a result, selecting an inefficient data type might quickly waste a lot of disk space. Always choose the data type with the lowest footprint depending on the data you anticipate being stored in it.
  • Performance — When it comes to performance, not all data types are created equal. Because it has less effort, the CHAR data type operators are 50% quicker than the VARCHAR data type operators.

When Should You Use String Data Types?

The string is one of the most frequent data types in SQL. Alphanumeric text is represented by the string. Consider the letters ‘a’, ‘abc123,’ or ‘adam-the-automator.’ A string is a collection of alphanumeric characters. A string might also be made up entirely of digits, such as 8125551212, which is a phone number.

When you need to store data like a name, physical address, email address, phone number, gender, or any other text, choosing one of numerous string data types is a smart option.


The CHAR data type is a suitable option when you need to store a string with a defined number of characters that does not exceed 255. The CHAR string data type allots a certain amount of RAM for data storage.

Numbers to call in the United States, for example, always contain ten digits. These Numbers to call have a set format and will never be longer than ten digits. For Numbers to call, storing them in a CHAR field with a size of 10 would be ideal.

VARCHAR stands for Variable Character (X)

VARCHAR data types are more versatile than CHAR data types. You may specify a maximum size rather than a fixed size using VARCHAR data types.

If you construct a VARCHAR data type with a maximum size of 10 but enter data that only takes up eight bytes, SQL will reduce the memory needed to just eight bytes instead of 10.


When filling out an online form, you usually don’t get a blank text box to enter your gender. Instead, it gives you a dropdown menu with options such as male and female. Use an ENUM SQL data type when you know the alternatives ahead of time.

You may control what data is entered into a field by using an ENUM data type.

Types of Text

TEXT data types are also available in SQL. These kinds are ideal for storing string data, such as long-form text strings with lengths ranging from one byte to four gigabytes. On e-commerce platforms, the TEXT data types are typically employed to hold the body of articles or possibly item descriptions.

The only significant distinction between the TEXT data types is the amount of data you can store in them.

Unlike the similar CHAR and VARCHAR data types, the various Types of Text don’t require you to specify a length.


The THE TEXT AND THE TINYTEXT SQL data types are great for data like quotes and Numbers to call. You can fit a maximum character count of 256 bytes and 64kb respectively into the TINYTEXT and TEXT data types


Use a text field, either MEDIUMTEXT or LONGTEXT, when you need to input a large number of alphanumeric characters into a field. The amount of text you wish to store will determine which of these two data types you choose.

The MEDIUMTEXT data type may be appropriate for storing a message that is less than 16MB, whereas LONGTEXT would be appropriate for storing an entire book that is less than 4GB.

Name Length Maximum Examples
CHAR 256bytes Various specific texts, such as corporate abbreviations and Numbers to call
VARCHAR ~64kb Names, locations, and a list of things are examples of nonspecific texts.
ENUM Unspecified Gender, height, and weight are all examples of discrete data.
MEDIUMTEXT ~16MB Perhaps a memo or an essay
LONGTEXT ~4GB An whole text book
TEXT ~64kb Numbers to call
TINYTEXT 256bytes  

When to Use Different Numeric Data Types

When you need to execute mathematical operations on SQL data, a numeric data type is the way to go. Numeric data types enable you to save numbers that will subsequently be utilized in a mathematical statement.

A numeric data type is appropriate for data such as an employee’s salary, which may be used to compute bonuses, the price of an item sold in a supermarket, which may be used to calculate sales tax, and so on.

Numeric data types are divided into two categories: those with decimal points and those without.


Use an integer when you need to store a number without a decimal point. Whole numbers are stored in integers. The count of an item is a nice example of data that may be stored as an integer. A grocery item’s price, on the other hand, would not change.

DEC(P,S) and NUM (fixed-point) (P)

When you need to store non-whole integers with a decimal point, a fixed point SQL data type is the way to go. A precision (P) and scale (S) value create fixed-point data types, which hold a fixed number.

The entire number of digits permitted is represented by the precision value, while the total number of digits to the right of the decimal point is represented by the scale value. 10.523, for instance, has a precision of five and a scale of three.

Set-point data types get their name from the fact that, like CHAR data types, they have a fixed amount of memory assigned to them. When you store 10.1 or 10.111, for example, a field created with a fixed-point data type with a precision of five and a scale of three will allocate the same amount of RAM since 10.1 will be saved as 10.100.

Fixed-point data types are ideal for number schemas that don’t change, such as money, where two digits to the right of the decimal point are always there.

Decimal (DEC) and numeric (NUM) are two fixed-point data types in SQL (NUM). Despite their similarities, NUM only enables you to specify a precision number, while DEC lets you to provide both a provision and a scale.

When a precision is supplied without a scale, DEC behaves as a numeric data type.

DOUBLE FLOAT(P) and Floating-Point – FLOAT(P)

When you need to store non-whole numbers but aren’t sure of their precise accuracy or scale, a floating-point data type is the way to go.

The way fixed-point and floating-point data types like FLOAT(P) and DOUBLE represent values in the system storage differs. When the rules of a fixed-point data type like DECIMAL are broken, it will issue a warning and truncate the data, however a floating-point data type will not provide a warning, as seen below.

When a fixed-point data type rule is broken, SQL issues a warning message.When a fixed-point data type rule is broken, SQL issues a warning message.

For storing the results of a math computation, floating-point data formats are ideal. A FLOAT data type, for example, will record the outcome of an arithmetic computation by rounding up the answer to the precision (P) specified.

Unsigned vs. Signed: What’s the Difference?

Both positive and negative numbers exist. In SQL, positive and negative integers are handled differently. A numeric data type must be signed in order to record a negative value. Negative and positive numbers are supported through signed data types.

Signed numeric data types provide values ranging from -128 to 127. Unsigned numeric data types, on the other hand, enable you to store values ranging from 0 to 255.

Name Character size (in bytes) Range of storage (unsigned) Range of storage (signed)
TINYINT 1 byte 0 to 255 a range of -128 to 128 bytes
TINYINT UNSIGNED ??? -255 255 bytes maximum
SMALLINT 2 bytes From 0 to 65535 -32KB -32KB -32KB -32KB -32KB
INT 4 bytes ranging from 0 to 4,294,967,295 -2B to 2B
MEDIUMINT 3 bytes ranging from 0 to 16,777,215 from -8MB to -8MB
BIGINT 8 bytes Between 0 and 18,446,744,073,709,551,615 -9ZB to 9ZBZBZBZBZBZBZBZBZZBZBZBZBZBZBZBZ
FLOAT 4 bytes Null from -2B to +2B
DECIMAL 1 byte + 1 byte (for the + or – sign) From 0 to 65,535 -32KB to +32KB -32KB -32KB -32KB -32
DOUBLE Bytes: 8 (twice the bytes of floats) Null -9ZB to 9ZBZBZBZBZBZBZBZBZZBZBZBZBZBZBZBZ

When Should You Use Date-Based Data Types?

Look at date or time-based data types if you need to record dates with specified timings. These data types are for storing a date or a date and time.


Choose the Date data type when you need to record a date without a specified time. In the pattern YYYY-MM-DD, the Date type contains the year, month, and day separated by a dash.


Use the DateTime data type to hold both a date and a time. Datetime data types hold dates in the same format as Date data types (YYYY-MM-DD) and include time in the format HH:MM:SS:MS down to the millisecond (MS).

Data Types for Binary Large Objects (BLOB) and When to Use Them

You learnt about storing text of some kind in the previous sections. It didn’t matter whether the “text” was a string, an integer, or a date; it was all “text.” In certain cases, storing binary data in your SQL database, such as files, makes sense. When this occurs, you should investigate the binary large object (BLOB) data type.

BLOB data types are ideal for storing items that are connected to one another, such as product photographs, Excel invoices, audio files, video clips, or any other form of file. SQL permits blob data types with capacities of many terabytes to represent binary data like this.

You have four distinct BLOB data types to choose from if you want to store files in a SQL database type: Tiny BLOB, BLOB, BLOB MEDIUM, and Long BLOB. Except for the maximum quantity you may store in each kind, each data type has the same features.

Name Character size (in bytes) Potential storage requirements
Tiny BLOB 1 byte 255bytes
BLOB 2 bytes ~65KB
BLOB MEDIUM 3 bytes ~16MB
Long BLOB 4 bytes ~4GB


You should now have a good understanding of how to choose a SQL data type. Furthermore, you’ve seen that SQL gives you a lot of alternatives when it comes to storing your crucial SQL data.

Can you think of a past project when you didn’t assign the correct data type and how it impacted your project in the long run now that you know some of the most frequent SQL data types and their characteristics?

The “sql data types pdf” is a document that provides an overview of the different SQL Server data types and when to use them.

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