Adds an initial limited implementations of geo features to SQL. This implementation is based on the [OpenGIS® Implementation Standard for Geographic information - Simple feature access](http://www.opengeospatial.org/standards/sfs), which is the current standard for GIS system implementation. This effort is concentrate on SQL option AKA ISO 19125-2.
Queries that are supported as a result of this initial implementation
Metadata commands
- `DESCRIBE table` - returns the correct column types `GEOMETRY` for geo shapes and geo points.
- `SHOW FUNCTIONS` - returns a list that includes supported `ST_` functions
- `SYS TYPES` and `SYS COLUMNS` display correct types `GEO_SHAPE` and `GEO_POINT` for geo shapes and geo points accordingly.
Returning geoshapes and geopoints from elasticsearch
- `SELECT geom FROM table` - returns the geoshapes and geo_points as libs/geo objects in JDBC or as WKT strings in console.
- `SELECT ST_AsWKT(geom) FROM table;` and `SELECT ST_AsText(geom) FROM table;`- returns the geoshapes ang geopoints in their WKT representation;
Using geopoints to elasticsearch
- The following functions will be supported for geopoints in queries, sorting and aggregations: `ST_GeomFromText`, `ST_X`, `ST_Y`, `ST_Z`, `ST_GeometryType`, and `ST_Distance`. In most cases when used in queries, sorting and aggregations, these function are translated into script. These functions can be used in the SELECT clause for both geopoints and geoshapes.
- `SELECT * FROM table WHERE ST_Distance(ST_GeomFromText(POINT(1 2), point) < 10;` - returns all records for which `point` is located within 10m from the `POINT(1 2)`. In this case the WHERE clause is translated into a range query.
Limitations:
Geoshapes cannot be used in queries, sorting and aggregations as part of this initial effort. In order to fully take advantage of geoshapes we would need to have access to geoshape doc values, which is coming in #37206. `ST_Z` cannot be used on geopoints in queries, sorting and aggregations since we don't store altitude in geo_point doc values.
Relates to #29872
Backport of #42031
Implement a more trivial case of the CASE expression which is
expressed as a traditional function with 2 or 3 arguments. e.g.:
IIF(a = 1, 'one', 'many')
IIF(a > 0, 'positive')
Closes: #40917
(cherry picked from commit add02f4f553ad472026dcc1eaa84245a0558a4b0)
Implement the ANSI SQL CASE expression which provides the if/else
functionality common to most programming languages.
The CASE expression can have multiple WHEN branches and becomes a
powerful tool for SQL queries as it can be used in SELECT, WHERE,
GROUP BY, HAVING and ORDER BY clauses.
Closes: #36200
(cherry picked from commit 8b2577406f47ae60d15803058921d128390af0b6)
After `TIME` SQL data type is introduced, implement
`CURRENT_TIME/CURTIME` functions similarly to CURRENT_TIMESTAMP
that return the system's current time (only, without the date part).
Closes: #40468
(cherry picked from commit 9feede781409d0e264ce45951a25b28ff129b187)
* Document MATCH and QUERY function predicates.
* Polish the functions pages and add a list of functions to the main Functions & Operators page.
(cherry picked from commit 4cec0ae1b962ec7ea011a290aec72740386eb808)
Introduce Histogram grouping function for bucketing/grouping data based
on a given range. Both date and numeric histograms are supported using
the appropriate range declaration (numbers vs intervals).
SELECT HISTOGRAM(number, 50) AS h FROM index GROUP BY h
SELECT HISTOGRAM(date, INTERVAL 1 YEAR) AS h FROM index GROUP BY h
In addition add multiply operator for Intervals
Add docs for intervals and histogram
Fix#36509
Split function section into multiple chapters
Add String functions
Add (small) section on Conversion/Cast functions
Add missing aggregation functions
Enable documentation testing (was disabled by accident). While at it,
fix failing tests
Improve spec tests to allow multi-line queries (useful for docs)
Add ability to ignore a spec test (name should end with -Ignore)
Igor Motov
Marios Trivyzas
Andrei Stefan
Costin Leau
Marios Trivyzas
Costin Leau
Lisa Cawley