How to decode base64 encoded string in MySQL?

This article mainly introduces how to decode base64 encoded strings in mysql, then we can achieve decoding through the FROM_BASE64() function.

In MySQL, the FROM_BASE64() function decodes a base-64 encoded string and returns the result. More specifically, it accepts a string encoded with the base-64 encoding rules used by TO_BASE64() and returns the decoded result as a binary string.

<strong>FROM_BASE64()</strong>The syntax is as follows:

FROM_BASE64(str)

The parameter str is the base-64 encoding you wish to decode String.

Example 1 - Basic usage

The following is an example to demonstrate basic usage:

SELECT FROM_BASE64('Q2F0');

Result:

+---------------------+
| FROM_BASE64('Q2F0') |
+---------------------+
| Cat                 |
+---------------------+

In this example, our parameter is Q2F0, which is Cat's base-64 encoded string.

We can get the base-64 encoded string by passing Cat to the TO_BASE64() function:

SELECT TO_BASE64('Cat');

Result:

+------------------+
| TO_BASE64('Cat') |
+------------------+
| Q2F0             |
+------------------+

Example 2 - A longer string

Here is an example using a longer string:

SELECT FROM_BASE64('TXkgY2F0IGxpa2VzIHRvIGNoYXNlIGVsZXBoYW50cyE=');

Result:

+-------------------------------------------------------------+
| FROM_BASE64('TXkgY2F0IGxpa2VzIHRvIGNoYXNlIGVsZXBoYW50cyE=') |
+-------------------------------------------------------------+
| My cat likes to chase elephants!                            |
+-------------------------------------------------------------+

Example 3 - Invalid Parameter

If the parameter is not a valid base-64 string, return NULL:

SELECT FROM_BASE64('Oops!');

Result:

+----------------------+
| FROM_BASE64('Oops!') |
+----------------------+
| NULL                 |
+----------------------+

Example 4 - NULL parameter

If you pass in NULL, you will also get the NULL:

SELECT FROM_BASE64(NULL);

result :

+-------------------+
| FROM_BASE64(NULL) |
+-------------------+
| NULL              |
+-------------------+

Example 5 - Missing Parameter

If you don't pass a parameter, you will get an error:

SELECT FROM_BASE64();

Result:

ERROR 1582 (42000): Incorrect parameter count in the call to native function 'FROM_BASE64'

Example 6 - Too Many Parameters

If you pass in too many parameters, you will also get an error:

SELECT FROM_BASE64('Q2F0', 'RWxlcGhhbnQ=');

Result:

ERROR 1582 (42000): Incorrect parameter count in the call to native function 'FROM_BASE64'

This article is about the method of decoding base64 encoded strings in MySQL. I hope it will be helpful to friends in need!

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