URL Encode / Decode

The url_encode function percent-encodes a string per RFC 3986. Only unreserved characters (A-Z, a-z, 0-9, -, _, ., ~) are left as-is — everything else is encoded as %XX with uppercase hex digits.

The url_decode function decodes percent-encoded strings back to their original form. It also decodes + as a space (for application/x-www-form-urlencoded compatibility). Invalid percent sequences (e.g., %ZZ, trailing %) are passed through literally.

Encode

D SELECT url_encode('hello world') AS encoded;
┌───────────────┐
│    encoded    │
│    varchar    │
├───────────────┤
│ hello%20world │
└───────────────┘

D SELECT url_encode('café') AS encoded;
┌───────────┐
│  encoded  │
│  varchar  │
├───────────┤
│ caf%C3%A9 │
└───────────┘

D SELECT url_encode('key=value&lang=en') AS encoded;
┌───────────────────────────┐
│          encoded          │
│          varchar          │
├───────────────────────────┤
│ key%3Dvalue%26lang%3Den   │
└───────────────────────────┘

Decode

D SELECT url_decode('hello%20world') AS decoded;
┌─────────────┐
│   decoded   │
│   varchar   │
├─────────────┤
│ hello world │
└─────────────┘

D SELECT url_decode('hello+world') AS decoded;
┌─────────────┐
│   decoded   │
│   varchar   │
├─────────────┤
│ hello world │
└─────────────┘

D SELECT url_decode('caf%C3%A9') AS decoded;
┌─────────┐
│ decoded │
│ varchar │
├─────────┤
│ café    │
└─────────┘

Round-trip

D SELECT url_decode(url_encode('https://example.com/path?q=hello world')) AS roundtrip;
┌──────────────────────────────────────────┐
│                roundtrip                 │
│                 varchar                  │
├──────────────────────────────────────────┤
│ https://example.com/path?q=hello world   │
└──────────────────────────────────────────┘

Returns an empty string for empty input and NULL for NULL input.