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Symbolic link
3.6 KiB
Symbolic link
3.6 KiB
IPv6
IPv6
是基于FixedString(16)
类型的domain类型,用来存储IPv6地址值。它使用紧凑的存储方式,提供用户友好的输入输出格式, 自动检查列类型。
基本用法
CREATE TABLE hits (url String, from IPv6) ENGINE = MergeTree() ORDER BY url;
DESCRIBE TABLE hits;
┌─name─┬─type───┬─default_type─┬─default_expression─┬─comment─┬─codec_expression─┐
│ url │ String │ │ │ │ │
│ from │ IPv6 │ │ │ │ │
└──────┴────────┴──────────────┴────────────────────┴─────────┴──────────────────┘
您也可以使用 IPv6
domain做主键:
CREATE TABLE hits (url String, from IPv6) ENGINE = MergeTree() ORDER BY from;
IPv6
domain支持定制化的IPv6地址字符串格式:
INSERT INTO hits (url, from) VALUES ('https://wikipedia.org', '2a02:aa08:e000:3100::2')('https://clickhouse.yandex', '2001:44c8:129:2632:33:0:252:2')('https://clickhouse.yandex/docs/en/', '2a02:e980:1e::1');
SELECT * FROM hits;
┌─url────────────────────────────────┬─from──────────────────────────┐
│ https://clickhouse.yandex │ 2001:44c8:129:2632:33:0:252:2 │
│ https://clickhouse.yandex/docs/en/ │ 2a02:e980:1e::1 │
│ https://wikipedia.org │ 2a02:aa08:e000:3100::2 │
└────────────────────────────────────┴───────────────────────────────┘
它以紧凑的二进制格式存储数值:
SELECT toTypeName(from), hex(from) FROM hits LIMIT 1;
┌─toTypeName(from)─┬─hex(from)────────────────────────┐
│ IPv6 │ 200144C8012926320033000002520002 │
└──────────────────┴──────────────────────────────────┘
Domain不可隐式转换为除FixedString(16)
以外的类型。如果要将IPv6
值转换为字符串,则必须使用IPv6NumToString()
函数显示地进行此操作:
SELECT toTypeName(s), IPv6NumToString(from) as s FROM hits LIMIT 1;
┌─toTypeName(IPv6NumToString(from))─┬─s─────────────────────────────┐
│ String │ 2001:44c8:129:2632:33:0:252:2 │
└───────────────────────────────────┴───────────────────────────────┘
或转换为 FixedString(16)
类型:
SELECT toTypeName(i), CAST(from as FixedString(16)) as i FROM hits LIMIT 1;
┌─toTypeName(CAST(from, 'FixedString(16)'))─┬─i───────┐
│ FixedString(16) │ <20><><EFBFBD> │
└───────────────────────────────────────────┴─────────┘