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?format=txt
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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?format=txt
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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?format=txt
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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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