# How the BIT_COUNT() function works in Mariadb?

MariaDB’s `BIT_COUNT()`

function is used to count the number of bits set to `1`

in a given integer.

The MariaDB `BIT_COUNT()`

function is used to count the number of bits set to `1`

in a given integer. This function is useful for scenarios such as analyzing binary data, counting flags in bitmasks, or simply understanding the composition of binary values.

## Syntax

The syntax for the MariaDB `BIT_COUNT()`

function is as follows:

```
BIT_COUNT(N)
```

This function accepts a single argument `N`

, which is an integer, and returns the count of bits set to `1`

.

## Examples

### Example 1: Counting Bits in a Number

This example demonstrates how to count the number of bits set to `1`

in the number `5`

:

```
SELECT BIT_COUNT(5);
```

```
+--------------+
| BIT_COUNT(5) |
+--------------+
| 2 |
+--------------+
```

The output is `2`

because the binary representation of `5`

is `101`

, which has two bits set to `1`

.

### Example 2: Counting Bits in Zero

Here we’ll see the result of counting bits in `0`

:

```
SELECT BIT_COUNT(0);
```

```
+--------------+
| BIT_COUNT(0) |
+--------------+
| 0 |
+--------------+
```

The output is `0`

because there are no bits set to `1`

in the binary representation of `0`

.

### Example 3: Counting Bits in a Negative Number

This example shows the bit count for a negative number:

```
SELECT BIT_COUNT(-1);
```

```
+---------------+
| BIT_COUNT(-1) |
+---------------+
| 64 |
+---------------+
```

The output is `64`

because, in a 64-bit system, the binary representation of `-1`

is all bits set to `1`

.

### Example 4: Using with a Table

To use `BIT_COUNT()`

with table data, let’s create a simple table:

```
DROP TABLE IF EXISTS example;
CREATE TABLE example (a INT);
INSERT INTO example VALUES (5), (0), (-1);
```

Now, let’s count the bits:

```
SELECT a, BIT_COUNT(a) FROM example;
```

```
+------+--------------+
| a | BIT_COUNT(a) |
+------+--------------+
| 5 | 2 |
| 0 | 0 |
| -1 | 64 |
+------+--------------+
```

The output shows the bit counts for each value in column `a`

.

### Example 5: Counting Bits in a Large Number

Let’s count the bits set to `1`

in a large number:

```
SELECT BIT_COUNT(123456789);
```

```
+----------------------+
| BIT_COUNT(123456789) |
+----------------------+
| 16 |
+----------------------+
```

The output is `16`

because the binary representation of `123456789`

has sixteen bits set to `1`

.

## Related Functions

Here are a few functions related to MariaDB’s `BIT_COUNT()`

:

- MariaDB’s
`BIT_AND()`

function is used to perform a bitwise AND operation on all bits in an expression. - MariaDB’s
`BIT_OR()`

function is used to perform a bitwise OR operation on all bits in an expression. - MariaDB’s
`BIT_XOR()`

function is used to perform a bitwise XOR operation on all bits in an expression.

## Conclusion

The `BIT_COUNT()`

function in MariaDB is a straightforward yet powerful tool for working with binary data. It allows for efficient analysis of bit patterns and can be used in a variety of applications, from data analysis to system programming. Understanding its usage and related functions can enhance your database querying capabilities.