Understanding Decimal Data Type in SQL Server

Hello Dev, if you are a developer or a database administrator working with SQL Server, then you know how important it is to understand different data types. Decimal data type is one such data type, which is widely used in SQL Server for storing decimal numbers. In this article, we will explore decimal data type in depth, including its syntax, usage, and storage, so that you can use it more effectively in your SQL Server projects.

What is Decimal Data Type?

Decimal data type is a numeric data type that is used to store decimal numbers in SQL Server. It is also known as numeric data type or exact numeric data type, as it allows you to store exact decimal values with high precision and scale. Decimal data type is used when you need to store decimal values with more precision than what is possible with other numeric data types, such as int or float.

Syntax of Decimal Data Type

The syntax of decimal data type in SQL Server is as follows:

Parameter	Description
DECIMAL[(p[,s])]	Specifies the precision and scale of the decimal value.

Here, p is the precision and s is the scale of the decimal value. Precision represents the total number of digits that can be stored in the decimal value, while scale represents the number of digits that can be stored to the right of the decimal point.

Usage of Decimal Data Type

Decimal data type is commonly used in financial and scientific applications where high precision decimal values are required. For example, you may use decimal data type to store currency values, interest rates, or scientific measurements. Decimal data type is also used in calculations involving money or financial matters, as it provides greater accuracy when performing arithmetic operations.

Storage of Decimal Data Type

Decimal data type is stored as a fixed-length numeric value in SQL Server. The number of bytes required for storage depends on the precision and scale of the decimal value. For example, if you have a decimal value with precision 10 and scale 2, then it will require 8 bytes of storage. The first byte represents the sign of the value (+ or -), while the remaining bytes represent the decimal value itself.

Creating Decimal Data Type in SQL Server

Creating Decimal Data Type Using T-SQL

You can create a decimal data type in SQL Server using T-SQL. The syntax for creating decimal data type is as follows:

CREATE TABLE table_name(column_name DECIMAL(p,s),...)

Here, table_name is the name of the table, column_name is the name of the column, and p and s are the precision and scale of the decimal value.

Creating Decimal Data Type Using SQL Server Management Studio

You can also create a decimal data type using SQL Server Management Studio. To do this, follow these steps:

1. Open SQL Server Management Studio and connect to your SQL Server.
2. Right-click on the database where you want to create the table and select “New Query”.
3. Enter the following SQL code to create a table with a decimal column:

CREATE TABLE table_name(column_name DECIMAL(p,s),...)

Working with Decimal Data Type in SQL Server

Inserting Decimal Data Type Values

To insert decimal data type values in SQL Server, use the following syntax:

INSERT INTO table_name (column_name) VALUES ( decimal_value )

Here, table_name is the name of the table, column_name is the name of the column, and decimal_value is the decimal value you want to insert.

Selecting Decimal Data Type Values

To select decimal data type values in SQL Server, use the following syntax:

SELECT column_name FROM table_name

Here, table_name is the name of the table, and column_name is the name of the decimal column you want to select.

Updating Decimal Data Type Values

To update decimal data type values in SQL Server, use the following syntax:

UPDATE table_name SET column_name = decimal_value WHERE condition

Here, table_name is the name of the table, column_name is the name of the decimal column you want to update, decimal_value is the new decimal value you want to set, and condition is the condition that specifies which rows to update.

FAQs about Decimal Data Type in SQL Server

Q. What is the maximum precision and scale of decimal data type in SQL Server?

The maximum precision of decimal data type in SQL Server is 38, while the maximum scale is 38.

Q. What is the difference between decimal data type and float data type?

Decimal data type allows you to store exact decimal values with high precision and scale, while float data type allows you to store approximate decimal values with lower precision and scale. Decimal data type should be used when you need to store exact decimal values, while float data type should be used when you need to store approximate decimal values.

Q. How do I convert decimal data type to other data types in SQL Server?

You can convert decimal data type to other data types in SQL Server using the CONVERT or CAST function. For example, to convert decimal data type to integer data type, use the following syntax:

CONVERT(INT, decimal_column)

Here, decimal_column is the name of the decimal column you want to convert.

Q. Can I perform arithmetic operations on decimal data type in SQL Server?

Yes, you can perform arithmetic operations on decimal data type in SQL Server. Decimal data type supports all arithmetic operations, such as addition, subtraction, multiplication, and division.

Q. Can decimal data type be used in indexes and constraints?

Yes, decimal data type can be used in indexes and constraints in SQL Server. You can create an index on a decimal column to improve query performance, and you can also create a constraint on a decimal column to enforce data integrity.

Conclusion

Decimal data type is a powerful data type in SQL Server that allows you to store exact decimal values with high precision and scale. By understanding how to create, insert, select, and update decimal data type values, you can take advantage of its benefits in your SQL Server projects. We hope this article has helped you understand decimal data type in depth, and we look forward to your feedback and comments.