SQL Server LOG10()

SQL Server LOG10() Function

The SQL Server LOG10() function returns the base-10 logarithm of a specified number. This function is useful for mathematical and scientific calculations involving logarithms.

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Syntax

SELECT LOG10(number);

The LOG10() function takes a single argument:

• number: The numeric expression for which to calculate the base-10 logarithm. The value must be greater than 0.

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Example SQL Server LOG10() Function Queries

Let's look at some examples of SQL Server LOG10() function queries:

1. Basic LOG10() Example

SELECT LOG10(1) AS result;

This query returns the base-10 logarithm of 1. The result will be:

result
------
0

2. LOG10() with a Positive Number

SELECT LOG10(10) AS result;

This query returns the base-10 logarithm of 10. The result will be:

result
------
1

3. LOG10() with a Column

SELECT value, LOG10(value) AS log10_value
FROM numbers;

This query returns the base-10 logarithm of the value column for each record in the numbers table. The result will show the original value and its corresponding log10_value.

4. LOG10() with a Variable

DECLARE @num FLOAT;
SET @num = 100;
SELECT LOG10(@num) AS result;

This query uses a variable to store a numeric value and then returns its base-10 logarithm. The result will be:

result
------
2

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Full Example

Let's go through a complete example that includes creating a table, inserting data, and using the LOG10() function.

Step 1: Creating a Table

This step involves creating a new table named example_table to store some sample data.

CREATE TABLE example_table (
    id INT PRIMARY KEY,
    value FLOAT
);

In this example, we create a table named example_table with columns for id and value.

Step 2: Inserting Data into the Table

This step involves inserting some sample data into the example_table.

INSERT INTO example_table (id, value) VALUES (1, 1);
INSERT INTO example_table (id, value) VALUES (2, 10);
INSERT INTO example_table (id, value) VALUES (3, 100);
INSERT INTO example_table (id, value) VALUES (4, 1000);

Here, we insert data into the example_table.

Step 3: Using the LOG10() Function

This step involves using the LOG10() function to return the base-10 logarithm of the value column.

SELECT id, value, LOG10(value) AS log10_value
FROM example_table;

This query retrieves the id, value, and the base-10 logarithm of the value column for each row in the example_table. The result will be:

id  value  log10_value
--- ------ -----------
1   1      0
2   10     1
3   100    2
4   1000   3

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Conclusion

The SQL Server LOG10() function is a powerful tool for returning the base-10 logarithm of a specified number. Understanding how to use the LOG10() function and its syntax is essential for effective mathematical and scientific calculations in SQL Server.