BASE64_DECODE_STRING¶

Syntax¶

BASE64_DECODE_STRING( <input> [ , <alphabet> ] )

Arguments¶

Required:

input

A Base64-encoded string expression.

Optional:

alphabet

A string consisting of up to three ASCII characters:

• The first two characters in the string specify the last two characters (indexes 62 and 63) in the alphabet used to encode the input:

  • A to Z (indexes 0-25)

  • a to z (indexes 26-51)

  • 0 to 9 (indexes 52-61)

  • + and / (indexes 62, 63)

  Defaults: + and /

• The third character in the string specifies the character used for padding.

  Default: =

Returns¶

A string.

Usage notes¶

• The characters in the alphabet string are positionally parsed; to specify different characters in the second or third positions in the string, you must explicitly specify all preceding characters even if you wish to use the defaults.

  For example:

  • +$ specifies the default (+) for index 62 and a different character ($) for index 63; no character is explicitly specified for padding so the default character (=) is used.

  • +/% specifies the defaults (+ and /) for indexes 62 and 63, and specifies a different character (%) for padding.

• The alphabet string used to decode input must match the string originally used to encode input.

For more information about base64 format, see base64.

Examples¶

This shows a simple example of using BASE64_DECODE_STRING:

SELECT BASE64_DECODE_STRING('U25vd2ZsYWtl');
+--------------------------------------+
| BASE64_DECODE_STRING('U25VD2ZSYWTL') |
|--------------------------------------|
| Snowflake                            |
+--------------------------------------+

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This shows another example of using BASE64_DECODE_STRING:

Create a table and data:

CREATE OR REPLACE TABLE base64_table (v VARCHAR, base64_string VARCHAR);
INSERT INTO base64_table (v) VALUES ('HELLO');
UPDATE base64_table SET base64_string = BASE64_ENCODE(v);

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Now run a query using BASE64_DECODE_STRING:

SELECT v, base64_string, BASE64_DECODE_STRING(base64_string) 
    FROM base64_table;
+-------+---------------+-------------------------------------+
| V     | BASE64_STRING | BASE64_DECODE_STRING(BASE64_STRING) |
|-------+---------------+-------------------------------------|
| HELLO | SEVMTE8=      | HELLO                               |
+-------+---------------+-------------------------------------+

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