[[sql-spec-syntax]]
=== SQL Statement Syntax

// Big list of the entire syntax in SQL

// Each entry might get its own file and code snippet

["source","sql",subs="attributes,callouts,macros"]
--------------------------------------------------
include-tagged::{sql-specs}/select.sql-spec[wildcardWithOrder]
--------------------------------------------------


[[sql-spec-syntax-order-by]]
==== `ORDER BY`

Elasticsearch supports `ORDER BY` for consistent ordering. You add
any field in the index that has <<doc-values,`doc_values`>> or
`SCORE()` to sort by `_score`. By default SQL sorts on what it
considers to be the most efficient way to get the results.

So sorting by a field looks like:

[source,js]
--------------------------------------------------
POST /_xpack/sql?format=txt
{
    "query": "SELECT * FROM library ORDER BY page_count DESC LIMIT 5"
}
--------------------------------------------------
// CONSOLE
// TEST[setup:library]

which results in something like:

[source,text]
--------------------------------------------------
     author      |        name        |  page_count   | release_date
-----------------+--------------------+---------------+------------------------
Peter F. Hamilton|Pandora's Star      |768            |2004-03-02T00:00:00.000Z
Vernor Vinge     |A Fire Upon the Deep|613            |1992-06-01T00:00:00.000Z
Frank Herbert    |Dune                |604            |1965-06-01T00:00:00.000Z
Alastair Reynolds|Revelation Space    |585            |2000-03-15T00:00:00.000Z
James S.A. Corey |Leviathan Wakes     |561            |2011-06-02T00:00:00.000Z
--------------------------------------------------
// TESTRESPONSE[s/\|/\\|/ s/\+/\\+/]
// TESTRESPONSE[_cat]

[[sql-spec-syntax-order-by-score]]
For sorting by score to be meaningful you need to include a full
text query in the `WHERE` clause. If you include multiple full
text queries in the `WHERE` clause then their scores will be
combined using the same rules as Elasticsearch's
<<query-dsl-bool-query,bool query>>. Here is a simple example:

[source,js]
--------------------------------------------------
POST /_xpack/sql?format=txt
{
    "query": "SELECT SCORE(), * FROM library WHERE match(name, 'dune') ORDER BY SCORE() DESC"
}
--------------------------------------------------
// CONSOLE
// TEST[setup:library]

Which results in something like:

[source,text]
--------------------------------------------------
    SCORE()    |    author     |       name        |  page_count   | release_date
---------------+---------------+-------------------+---------------+------------------------
2.288635       |Frank Herbert  |Dune               |604            |1965-06-01T00:00:00.000Z
1.8893257      |Frank Herbert  |Dune Messiah       |331            |1969-10-15T00:00:00.000Z
1.6086555      |Frank Herbert  |Children of Dune   |408            |1976-04-21T00:00:00.000Z
1.4005898      |Frank Herbert  |God Emperor of Dune|454            |1981-05-28T00:00:00.000Z
--------------------------------------------------
// TESTRESPONSE[s/\|/\\|/ s/\+/\\+/ s/\(/\\\(/ s/\)/\\\)/]
// TESTRESPONSE[_cat]

Note that you can return `SCORE()` by adding it to the where clause. This
is possible even if you are not sorting by `SCORE()`:

[source,js]
--------------------------------------------------
POST /_xpack/sql?format=txt
{
    "query": "SELECT SCORE(), * FROM library WHERE match(name, 'dune') ORDER BY page_count DESC"
}
--------------------------------------------------
// CONSOLE
// TEST[setup:library]

[source,text]
--------------------------------------------------
    SCORE()    |    author     |       name        |  page_count   | release_date
---------------+---------------+-------------------+---------------+------------------------
2.288635       |Frank Herbert  |Dune               |604            |1965-06-01T00:00:00.000Z
1.4005898      |Frank Herbert  |God Emperor of Dune|454            |1981-05-28T00:00:00.000Z
1.6086555      |Frank Herbert  |Children of Dune   |408            |1976-04-21T00:00:00.000Z
1.8893257      |Frank Herbert  |Dune Messiah       |331            |1969-10-15T00:00:00.000Z
--------------------------------------------------
// TESTRESPONSE[s/\|/\\|/ s/\+/\\+/ s/\(/\\\(/ s/\)/\\\)/]
// TESTRESPONSE[_cat]


[[sql-spec-syntax-extract]]
==== `EXTRACT`

Elasticsearch supports `EXTRACT` to extract fields from datetimes.
You can run any <<sql-functions-datetime,datetime function>>
with `EXTRACT(<datetime_function> FROM <expression>)`. So

["source","sql",subs="attributes,callouts,macros"]
--------------------------------------------------
include-tagged::{sql-specs}/datetime.csv-spec[extractDayOfYear]
--------------------------------------------------

is the equivalent to

["source","sql",subs="attributes,callouts,macros"]
--------------------------------------------------
include-tagged::{sql-specs}/datetime.csv-spec[dayOfYear]
--------------------------------------------------