The Real data type in SQL is used to store floating-point numbers with a decimal precision. It is often confused with other numeric data types such as Integer or Decimal, but it has its unique characteristics and use cases.
Real Data Type
The Real data type in SQL is used to store single-precision floating-point numbers. It can hold values ranging from -3.40E+38 to -1.18E-38, 0, and 1.18E-38 to 3.40E+38. This data type is commonly used when precision is not critical, and using less storage space is preferred.
Declaration and Usage
To declare a column with the Real data type, you can use the following syntax:
CREATE TABLE myTable (
myColumn REAL
);
You can also use the Real data type when creating temporary tables:
CREATE TEMPORARY TABLE myTempTable (
myColumn REAL
);
When inserting values into a column of the Real data type, you can use the following syntax:
INSERT INTO myTable (myColumn)
VALUES (3.14);
Comparison with Other Numeric Data Types
It’s important to note that the Real data type has limitations compared to other numeric data types.
- The Real data type has lower precision compared to Decimal or Numeric types.
- It occupies less storage space than Decimal or Numeric types.
- Real numbers are approximate, which means they may not be exact representations of decimal values.
- The precision of Real numbers depends on the system architecture.
When precise calculations are required, it is recommended to use the Decimal or Numeric data types instead of Real.
Examples:
Let’s consider some examples to understand the Real data type better.
Example 1: Storing Temperature Readings
Suppose you have a table to store temperature readings from various sensors. Since temperature readings are not always precise to multiple decimal places, using the Real data type can be a suitable choice. For example:
CREATE TABLE temperatureData (
sensorId INT,
reading REAL
);
Example 2: Calculating Average
If you need to calculate the average of a set of values, using the Real data type can be efficient. However, keep in mind that it may introduce slight inaccuracies due to its approximate nature.
SELECT AVG(reading) FROM temperatureData;
Summary
In summary, the Real data type in SQL is used to store single-precision floating-point numbers. It is suitable for scenarios where precision is not critical, and storage space optimization is desired. However, it’s important to be aware of its limitations and use more precise data types like Decimal or Numeric when necessary.
I hope this article has provided you with a clear understanding of the Real data type in SQL and how it differs from other numeric data types.