mirror of https://github.com/apache/druid.git
57 lines
2.8 KiB
Markdown
57 lines
2.8 KiB
Markdown
---
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id: sorting-orders
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title: "String comparators"
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---
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> Apache Druid supports two query languages: [Druid SQL](sql.md) and [native queries](querying.md).
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> This document describes the native
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> language. For information about functions available in SQL, refer to the
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> [SQL documentation](sql.md#scalar-functions).
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These sorting orders are used by the [TopNMetricSpec](./topnmetricspec.md), [SearchQuery](./searchquery.md), GroupByQuery's [LimitSpec](./limitspec.md), and [BoundFilter](./filters.md#bound-filter).
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## Lexicographic
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Sorts values by converting Strings to their UTF-8 byte array representations and comparing lexicographically, byte-by-byte.
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## Alphanumeric
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Suitable for strings with both numeric and non-numeric content, e.g.: "file12 sorts after file2"
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See https://github.com/amjjd/java-alphanum for more details on how this ordering sorts values.
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This ordering is not suitable for numbers with decimal points or negative numbers.
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* For example, "1.3" precedes "1.15" in this ordering because "15" has more significant digits than "3".
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* Negative numbers are sorted after positive numbers (because numeric characters precede the "-" in the negative numbers).
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## Numeric
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Sorts values as numbers, supports integers and floating point values. Negative values are supported.
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This sorting order will try to parse all string values as numbers. Unparseable values are treated as nulls, and nulls precede numbers.
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When comparing two unparseable values (e.g., "hello" and "world"), this ordering will sort by comparing the unparsed strings lexicographically.
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## Strlen
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Sorts values by their string lengths. When there is a tie, this comparator falls back to using the String compareTo method.
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## Version
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Sorts values as versions, e.g.: "10.0 sorts after 9.0", "1.0.0-SNAPSHOT sorts after 1.0.0".
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See https://maven.apache.org/ref/3.6.0/maven-artifact/apidocs/org/apache/maven/artifact/versioning/ComparableVersion.html for more details on how this ordering sorts values. |