How to Use CONV Function in MySQL: Syntax and Examples

In MySQL, the CONV() function converts a number from one base to another base. You provide the number as a string, the base it is currently in, and the base you want to convert it to, like CONV('a', 16, 10) to convert hexadecimal 'a' to decimal 10.

Syntax

The CONV() function syntax is:

• CONV(number, from_base, to_base)

where:

• number: The number as a string to convert.
• from_base: The base of the input number (between 2 and 36).
• to_base: The base to convert the number to (between 2 and 36).

The function returns the converted number as a string.

sql

CONV(number, from_base, to_base)

Example

This example converts the hexadecimal number '1a' to decimal, binary, and octal bases.

sql

SELECT 
  CONV('1a', 16, 10) AS decimal_value,
  CONV('1a', 16, 2) AS binary_value,
  CONV('1a', 16, 8) AS octal_value;

Output

decimal_value | binary_value | octal_value
------------- | ------------ | -----------
26            | 11010        | 32

Common Pitfalls

Common mistakes when using CONV() include:

• Passing a number instead of a string for the number argument, which can cause unexpected results.
• Using bases outside the allowed range (2 to 36), which returns NULL.
• Confusing the input base and output base order.

Always provide the number as a string and verify base values.

sql

/* Wrong: number as integer */
SELECT CONV(10, 10, 2);

/* Right: number as string */
SELECT CONV('10', 10, 2);

Output

/* Wrong returns NULL or unexpected result depending on MySQL version */
/* Right returns '1010' */

Quick Reference

Parameter	Description	Allowed Values
number	Number to convert (as string)	Any valid number string in from_base
from_base	Base of the input number	2 to 36
to_base	Base to convert the number to	2 to 36

Key Takeaways

Use CONV() to convert numbers between bases by specifying the number as a string and the from/to bases.

Both from_base and to_base must be between 2 and 36, or CONV() returns NULL.

Always pass the number argument as a string to avoid unexpected results.

CONV() returns the converted number as a string, not a numeric type.