Understanding Decimal in SQL Server for Devs

Hey there, Dev! If you’re working with SQL Server, chances are you’ve come across the decimal data type. In this article, we’ll dive into what decimal is, how to use it, and some frequently asked questions about it.

What is Decimal in SQL Server?

Decimal is a numeric data type in SQL Server that allows for precise storage and calculation of decimal numbers. Unlike other numeric data types like int or float, decimal can store values with a specific number of digits both before and after the decimal point.

To specify a decimal value in SQL Server, you use the syntax DECIMAL(precision, scale), where precision is the total number of digits and scale is the number of digits to the right of the decimal point.

Example:

To create a decimal column in a table with a precision of 10 and a scale of 2, you would use the following syntax:

Column Name	Data Type
Price	DECIMAL(10,2)

This would allow you to store values like 12345.67 or 9876.54 in the Price column.

Using Decimal in SQL Server

Now that we know what decimal is, let’s look at how to use it in SQL Server.

Creating Decimal Columns

To create a decimal column in a table, you can use the DECIMAL data type in your column definition.

Example:

CREATE TABLE Products (Id INT PRIMARY KEY,Name VARCHAR(50),Price DECIMAL(10,2));

This would create a Products table with an Id column, a Name column with a maximum length of 50 characters, and a Price column with a precision of 10 and a scale of 2.

Inserting Data into Decimal Columns

When inserting data into a decimal column, you must format the value as a decimal number.

Example:

INSERT INTO Products (Id, Name, Price)VALUES (1, 'Widget', 12.99);

This would insert a row into the Products table with an Id of 1, a Name of ‘Widget’, and a Price of 12.99.

Using Decimal in Calculations

Decimal values can also be used in calculations in SQL Server.

Example:

SELECT Price * 0.15 AS TaxFROM ProductsWHERE Name = 'Widget';

This would calculate the tax on the Widget product by multiplying its Price by 0.15 (for a 15% tax rate).

FAQ

What’s the difference between decimal and numeric?

Both decimal and numeric are numeric data types in SQL Server that allow for precise storage and calculation of decimal numbers. The main difference between them is in their syntax – decimal uses the keyword DECIMAL, while numeric uses the keyword NUMERIC. Otherwise, they function the same way.

What’s the maximum precision and scale for decimal in SQL Server?

The maximum precision for decimal in SQL Server is 38, and the maximum scale is 38. However, keep in mind that using the maximum precision and scale can have performance implications.

When should I use decimal instead of float?

You should use decimal instead of float when you need precise storage and calculation of decimal numbers, such as when working with financial data.

Can I perform calculations between decimal and other numeric data types?

Yes, you can perform calculations between decimal and other numeric data types in SQL Server. However, keep in mind that the result may be rounded or truncated depending on the data types involved.

Can I convert a decimal value to a string?

Yes, you can convert a decimal value to a string using the CAST or CONVERT functions in SQL Server.

Conclusion

Decimal is an important data type in SQL Server that allows for precise storage and calculation of decimal numbers. By understanding how to use it and some frequently asked questions, you can better work with decimal values in your SQL Server applications.