DECODE function

The DECODE function is the counterpart to the ENCODE function, which is used to convert a string to a binary format using a specific character encoding. The DECODE function takes the binary data and converts it back to a readable string format using the specified character encoding.

This function is useful when you need to work with binary data stored in a database and need to present it in a human-readable format, or when you need to convert data between different character encodings.

Syntax

decode(expr, charset)

Arguments

Return type

The DECODE function returns a STRING.

Example

The following example has a table called messages with a column called message_text that stores message data in a binary format using the UTF-8 character encoding. The DECODE function converts the binary data back to a readable string format. The output of this query is the readable text of the message stored in the messages table, with the ID 123, converted from the binary format to a string using the 'utf-8' encoding.

SELECT decode(message_text, 'utf-8') AS message
FROM messages
WHERE message_id = 123;