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876aebf7e0
This allows any datetime function to be present in `EXTRACT` which feels more consistent. `EXTRACT(FOO FROM bar)` is now just sugar for `FOO(bar)`. This is *much* simpler to explain in the documentation then "these 10 fields are supported by extract and they are the same as this subset of the datetime functions." The implementation of this is a little simpler then the old way. Instead of resolving the function in the parser we create an `UnresolvedFunction` that looks *almost* just like what we'd create for a single argument function and resolve the function in the `Analyzer`. This feels like a net positive as it allows us to group `EXTRACT` resolution failures with other function resolution failures. This also creates `UnresolvedFunctionTests` and `UnresolvedAttributeTests`. I had to create `UnresolvedFunctionTests` because `UnreolvedFunction` now has three boolean parameters which is incompatible with the generic `NodeSubclassTests`'s requirement that all ctor parameters be unique. I created `UnresolvedAttributeTests` because I didn't want `UnresolvedFunctionTests` to call `NodeSubclassTests` and figured that we'd want `UnresolvedAttributeTest` eventually and now felt like as good a time as any. Added a Original commit: elastic/x-pack-elasticsearch@358aada308
124 lines
4.8 KiB
Plaintext
124 lines
4.8 KiB
Plaintext
[[sql-spec-syntax]]
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=== SQL Statement Syntax
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// Big list of the entire syntax in SQL
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// Each entry might get its own file and code snippet
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["source","sql",subs="attributes,callouts,macros"]
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--------------------------------------------------
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include-tagged::{sql-specs}/select.sql-spec[wildcardWithOrder]
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--------------------------------------------------
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[[sql-spec-syntax-order-by]]
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==== `ORDER BY`
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Elasticsearch supports `ORDER BY` for consistent ordering. You add
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any field in the index that has <<doc-values,`doc_values`>> or
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`SCORE()` to sort by `_score`. By default SQL sorts on what it
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considers to be the most efficient way to get the results.
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So sorting by a field looks like:
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[source,js]
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--------------------------------------------------
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POST /_xpack/sql
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{
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"query": "SELECT * FROM library ORDER BY page_count DESC LIMIT 5"
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}
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--------------------------------------------------
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// CONSOLE
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// TEST[setup:library]
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which results in something like:
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[source,text]
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--------------------------------------------------
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author | name | page_count | release_date
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-----------------+--------------------+---------------+------------------------
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Peter F. Hamilton|Pandora's Star |768 |2004-03-02T00:00:00.000Z
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Vernor Vinge |A Fire Upon the Deep|613 |1992-06-01T00:00:00.000Z
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Frank Herbert |Dune |604 |1965-06-01T00:00:00.000Z
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Alastair Reynolds|Revelation Space |585 |2000-03-15T00:00:00.000Z
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James S.A. Corey |Leviathan Wakes |561 |2011-06-02T00:00:00.000Z
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--------------------------------------------------
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// TESTRESPONSE[s/\|/\\|/ s/\+/\\+/]
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// TESTRESPONSE[_cat]
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[[sql-spec-syntax-order-by-score]]
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For sorting by score to be meaningful you need to include a full
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text query in the `WHERE` clause. If you include multiple full
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text queries in the `WHERE` clause then their scores will be
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combined using the same rules as Elasticsearch's
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<<query-dsl-bool-query,bool query>>. Here is a simple example:
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[source,js]
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--------------------------------------------------
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POST /_xpack/sql
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{
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"query": "SELECT SCORE(), * FROM library WHERE match(name, 'dune') ORDER BY SCORE() DESC"
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}
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--------------------------------------------------
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// CONSOLE
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// TEST[setup:library]
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Which results in something like:
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[source,text]
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--------------------------------------------------
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SCORE() | author | name | page_count | release_date
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---------------+---------------+-------------------+---------------+------------------------
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2.288635 |Frank Herbert |Dune |604 |1965-06-01T00:00:00.000Z
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1.8893257 |Frank Herbert |Dune Messiah |331 |1969-10-15T00:00:00.000Z
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1.6086555 |Frank Herbert |Children of Dune |408 |1976-04-21T00:00:00.000Z
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1.4005898 |Frank Herbert |God Emperor of Dune|454 |1981-05-28T00:00:00.000Z
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--------------------------------------------------
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// TESTRESPONSE[s/\|/\\|/ s/\+/\\+/ s/\(/\\\(/ s/\)/\\\)/]
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// TESTRESPONSE[_cat]
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Note that you can return `SCORE()` by adding it to the where clause. This
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is possible even if you are not sorting by `SCORE()`:
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[source,js]
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--------------------------------------------------
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POST /_xpack/sql
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{
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"query": "SELECT SCORE(), * FROM library WHERE match(name, 'dune') ORDER BY page_count DESC"
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}
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--------------------------------------------------
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// CONSOLE
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// TEST[setup:library]
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[source,text]
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--------------------------------------------------
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SCORE() | author | name | page_count | release_date
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---------------+---------------+-------------------+---------------+------------------------
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2.288635 |Frank Herbert |Dune |604 |1965-06-01T00:00:00.000Z
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1.4005898 |Frank Herbert |God Emperor of Dune|454 |1981-05-28T00:00:00.000Z
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1.6086555 |Frank Herbert |Children of Dune |408 |1976-04-21T00:00:00.000Z
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1.8893257 |Frank Herbert |Dune Messiah |331 |1969-10-15T00:00:00.000Z
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--------------------------------------------------
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// TESTRESPONSE[s/\|/\\|/ s/\+/\\+/ s/\(/\\\(/ s/\)/\\\)/]
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// TESTRESPONSE[_cat]
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[[sql-spec-syntax-extract]]
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==== `EXTRACT`
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Elasticsearch supports `EXTRACT` to extract fields from datetimes.
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You can run any <<sql-functions-datetime,datetime function>>
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with `EXTRACT(<datetime_function> FROM <expression>)`. So
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["source","sql",subs="attributes,callouts,macros"]
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--------------------------------------------------
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include-tagged::{sql-specs}/datetime.csv-spec[extractDayOfYear]
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--------------------------------------------------
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is the equivalent to
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["source","sql",subs="attributes,callouts,macros"]
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--------------------------------------------------
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include-tagged::{sql-specs}/datetime.csv-spec[dayOfYear]
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--------------------------------------------------
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