How the BIT_COUNT() function works in Mariadb?

The BIT_COUNT() function is an aggregate function that returns the number of bits that are set in a given expression.

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The BIT_COUNT() function is an aggregate function that returns the number of bits that are set in a given expression. The BIT_COUNT() function can be used to count the number of bits that are 1 in a binary value, such as a column, a group, or a table. For example, the BIT_COUNT() function can be used to count the number of bits that are 1 in a column.

Syntax

The syntax of the BIT_COUNT() function is as follows:

BIT_COUNT(expression)

The expression parameter can be any valid numeric expression, such as a column name, a literal value, or a function call. The expression parameter is the expression that you want to count the number of bits that are 1 in. The expression parameter cannot be NULL.

The BIT_COUNT() function returns a numeric value, which is the number of bits that are 1 in the input expression. If the input expression is NULL or contains no values, the BIT_COUNT() function returns NULL.

Examples

Here are some examples of using the BIT_COUNT() function in Mariadb:

Example 1: Number of bits that are 1 in a literal expression

To get the number of bits that are 1 in a literal expression, you can simply pass the expression as the parameter. For example:

SELECT BIT_COUNT(1 + 2 + 3 + 4 + 5) AS result;

This statement returns 3 as the output, which is the number of bits that are 1 in the expression 1 + 2 + 3 + 4 + 5.

Example 2: Number of bits that are 1 in a column

To get the number of bits that are 1 in a column, you can use the column name as the parameter. For example, suppose you have a table called numbers that stores a single column of numeric values. You can use the BIT_COUNT() function to get the number of bits that are 1 in each value in the column. For example:

SELECT value, BIT_COUNT(value) AS result
FROM numbers;

This statement returns the value and the number of bits that are 1 in each value in the numbers table. For example, if the table contains the following data:

value
1
2
3
4
5

The statement returns the following output:

value result
1 1
2 1
3 2
4 1
5 2

Example 3: Number of bits that are 1 in a group

To get the number of bits that are 1 in a group, you can use the BIT_COUNT() function with the GROUP BY clause. For example, suppose you have a table called sales that stores the date, the product, and the quantity of each sale. You can use the BIT_COUNT() function with the GROUP BY clause to get the number of bits that are 1 in the quantity of each product sold in each month. For example:

SELECT DATE_FORMAT(date, '%Y-%m') AS month, product, BIT_COUNT(quantity) AS result
FROM sales
GROUP BY month, product;

This statement returns the month, the product, and the number of bits that are 1 in the quantity for each group in the sales table. For example, if the table contains the following data:

date product quantity
2023-01-01 Apple 10
2023-01-02 Banana 20
2023-01-03 Cherry 30
2023-01-04 Durian 40
2023-01-05 Eggplant 50
2023-02-01 Apple 15
2023-02-02 Banana 25
2023-02-03 Cherry 35
2023-02-04 Durian 45
2023-02-05 Eggplant 55

The statement returns the following output:

month product result
2023-01 Apple 2
2023-01 Banana 2
2023-01 Cherry 4
2023-01 Durian 2
2023-01 Eggplant 4
2023-02 Apple 3
2023-02 Banana 3
2023-02 Cherry 3
2023-02 Durian 3
2023-02 Eggplant 3

Example 4: Number of bits that are 1 in a table

To get the number of bits that are 1 in a table, you can use the BIT_COUNT() function with the * symbol. For example, suppose you have a table called numbers that stores a single column of numeric values. You can use the BIT_COUNT() function with the * symbol to get the number of bits that are 1 in all values in the table. For example:

SELECT BIT_COUNT(*) AS result
FROM numbers;

This statement returns the number of bits that are 1 in all values in the numbers table. For example, if the table contains the following data:

value
1
2
3
4
5

The statement returns 7 as the output, which is the number of bits that are 1 in all values in the table.

Example 5: Number of bits that are 1 in a NULL value

To get the number of bits that are 1 in a NULL value, you can use the NULL value as the parameter. However, the BIT_COUNT() function will return NULL as the output, because the input value is NULL. For example:

SELECT BIT_COUNT(NULL) AS result;

This statement returns NULL as the output, because the input value is NULL.

Some of the functions that are related to the BIT_COUNT() function are:

  • The BIT_AND() function, which returns the bitwise AND of all values in a given expression. The BIT_AND() function can be used to perform bitwise operations on a set of values, such as a column, a group, or a table. For example, the BIT_AND() function can be used to get the bitwise AND of all values in a column.
  • The BIT_OR() function, which returns the bitwise OR of all values in a given expression. The BIT_OR() function can be used to perform bitwise operations on a set of values, such as a column, a group, or a table. For example, the BIT_OR() function can be used to get the bitwise OR of all values in a column.
  • The BIT_XOR() function, which returns the bitwise XOR of all values in a given expression. The BIT_XOR() function can be used to perform bitwise operations on a set of values, such as a column, a group, or a table. For example, the BIT_XOR() function can be used to get the bitwise XOR of all values in a column.

Conclusion

The BIT_COUNT() function is a useful function that can help you count the number of bits that are 1 in a given expression in Mariadb. You can use it with any valid numeric expression, such as a column name, a literal value, or a function call. The BIT_COUNT() function returns a numeric value, which is the number of bits that are 1 in the input expression. You can also use some other functions that are related to the BIT_COUNT() function, such as the BIT_AND(), BIT_OR(), and BIT_XOR() functions.