How the BIT_LENGTH() function works in Mariadb?

MariaDB’s BIT_LENGTH() function is used to determine the length of a string in bits.

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The MariaDB BIT_LENGTH() function is used to determine the length of a string in bits. It is commonly utilized in scenarios where precise control over data storage and retrieval is required, such as in systems that handle binary data or when optimizing database storage.

Syntax

The syntax for the MariaDB BIT_LENGTH() function is as follows:

BIT_LENGTH(str)

This function accepts a string str as an argument and returns the length of the string in bits.

Examples

Example 1: Basic Usage

This example shows how to find the bit length of a simple string:

SELECT BIT_LENGTH('MariaDB');

+-----------------------+
| BIT_LENGTH('MariaDB') |
+-----------------------+
|                    56 |
+-----------------------+

The output is 56 because the string ‘MariaDB’ consists of 7 characters, and each character is 8 bits long, resulting in a total of 56 bits.

Example 2: Bit Length of an Empty String

Here we’ll see the bit length of an empty string:

SELECT BIT_LENGTH('');

+----------------+
| BIT_LENGTH('') |
+----------------+
|              0 |
+----------------+

The output is 0 because an empty string contains no characters, hence no bits.

Example 3: Bit Length of a Numeric Value

This example demonstrates the bit length of a numeric value treated as a string:

SELECT BIT_LENGTH('12345');

+---------------------+
| BIT_LENGTH('12345') |
+---------------------+
|                  40 |
+---------------------+

The output is 40 because the string ‘12345’ has 5 characters, and with each character being 8 bits, it totals to 40 bits.

Example 4: Using with a Table

To use BIT_LENGTH() with table data, let’s create a simple table:

DROP TABLE IF EXISTS example;
CREATE TABLE example (text VARCHAR(100));
INSERT INTO example VALUES ('Hello'), ('World'), ('!');

Now, let’s find the bit lengths:

SELECT text, BIT_LENGTH(text) FROM example;

+-------+------------------+
| text  | BIT_LENGTH(text) |
+-------+------------------+
| Hello |               40 |
| World |               40 |
| !     |                8 |
+-------+------------------+

The output shows the bit lengths for each string in the column text.

Example 5: Bit Length of a Unicode String

Let’s find the bit length of a Unicode string:

SELECT BIT_LENGTH('你好');

+----------------------+
| BIT_LENGTH('你好')   |
+----------------------+
|                   48 |
+----------------------+

The output is 48 because the string ‘你好’ consists of 2 Unicode characters, and assuming each character is encoded with 3 bytes (24 bits), it results in a total of 48 bits.

Here are a few functions related to MariaDB’s BIT_LENGTH():

  • MariaDB’s CHAR_LENGTH() function is used to return the number of characters in a string.
  • MariaDB’s OCTET_LENGTH() function is used to return the length of a string in bytes.
  • MariaDB’s LENGTH() function is used to return the length of a string in bytes.

Conclusion

The BIT_LENGTH() function in MariaDB is a useful tool for understanding the size of data in terms of bits. It is especially helpful when dealing with binary data or when optimizing data storage. By using BIT_LENGTH() alongside related functions, one can gain a comprehensive understanding of data size and structure within a database.