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Posted to commits@geode.apache.org by rv...@apache.org on 2016/09/30 00:33:50 UTC
[43/50] [abbrv] incubator-geode git commit: Draft of OQL aggregates
documentation. [#130418485]
Draft of OQL aggregates documentation. [#130418485]
- Needs revision to implement formatting/style/prose to
indicate its experimental status.
- Incomplete: changes not incoporporated into the grammar
definition, because the grammar is not up to date.
- Examples should be added (and verified) for each of the functions.
Project: http://git-wip-us.apache.org/repos/asf/incubator-geode/repo
Commit: http://git-wip-us.apache.org/repos/asf/incubator-geode/commit/e1ffcd10
Tree: http://git-wip-us.apache.org/repos/asf/incubator-geode/tree/e1ffcd10
Diff: http://git-wip-us.apache.org/repos/asf/incubator-geode/diff/e1ffcd10
Branch: refs/staging/docs-grant1
Commit: e1ffcd10a9d90671465a5f961d9d908fa00c9334
Parents: d12bc23
Author: Karen Miller <km...@pivotal.io>
Authored: Wed Sep 21 14:00:15 2016 -0700
Committer: Karen Miller <km...@pivotal.io>
Committed: Wed Sep 21 14:00:15 2016 -0700
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.../the_select_statement.html.md.erb | 118 +++++++++++++++++++
...ictions_and_unsupported_features.html.md.erb | 14 ++-
2 files changed, 130 insertions(+), 2 deletions(-)
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http://git-wip-us.apache.org/repos/asf/incubator-geode/blob/e1ffcd10/developing/query_select/the_select_statement.html.md.erb
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diff --git a/developing/query_select/the_select_statement.html.md.erb b/developing/query_select/the_select_statement.html.md.erb
index 04d14df..04f9f3b 100644
--- a/developing/query_select/the_select_statement.html.md.erb
+++ b/developing/query_select/the_select_statement.html.md.erb
@@ -201,3 +201,121 @@ FROM /exampleRegion p, p.positions.values pos
WHERE p.ID > 0 OR p.status = 'active' OR pos.secId
OR pos.secId = 'IBM'
```
+
+<div style="background-color:lightyellow;">
+<h2>(Experimental Feature) Aggregate Functions</h2>
+
+<p>
+Some prose here about being experimental.
+</p>
+
+<p>
+The aggregate functions
+<code>MIN</code>,
+<code>MAX</code>,
+<code>AVG</code>,
+<code>AVG</code> over a DISTINCT expression,
+<code>SUM</code> over a DISTINCT expression,
+<code>COUNT</code>, and
+<code>COUNT</code> over a DISTINCT expression
+are supported.
+The <code>GROUP BY</code> extension is also supported where appropriate.
+</p>
+
+<p>
+The <code>MIN</code> function returns the smallest of the selected
+expression.
+The type of the expression must evaluate to a
+<code>java.lang.Comparable</code>.
+</p>
+
+<p>
+The <code>MAX</code> function returns the largest of the selected
+expression.
+The type of the expression must evaluate to a
+<code>java.lang.Comparable</code>.
+</p>
+
+<p>
+The <code>AVG</code> function returns the arithmetic mean of the set
+formed by the selected expression.
+The type of the expression must evaluate to a
+<code>java.lang.Number</code>.
+For partitioned regions,
+each node's buckets provide both a sum and the number of elements
+to the node executing the query,
+such that a correct average may be computed.
+</p>
+
+<p>
+The <code>AVG</code> function where the DISTINCT modifier is applied
+to the expression returns the arithmetic mean of the set
+of unique (distinct) values.
+The type of the expression must evaluate to a
+<code>java.lang.Number</code>.
+For partitioned regions,
+the distinct values in a node's buckets are returned
+to the node executing the query.
+The query node can then calculate the avarage over
+the values that are unique across nodes,
+after eliminating duplicate values that come from separate nodes.
+</p>
+
+<p>
+The <code>SUM</code> function returns the sum over the set
+formed by the selected expression.
+The type of the expression must evaluate to a
+<code>java.lang.Number</code>.
+For partitioned regions,
+each node's buckets compute a sum over that node,
+returning that sum
+to the node executing the query,
+when then sums across all nodes.
+</p>
+
+<p>
+The <code>SUM</code> function where the DISTINCT modifier is applied
+to the expression returns the sum over the set
+of unique (distinct) values.
+The type of the expression must evaluate to a
+<code>java.lang.Number</code>.
+For partitioned regions,
+the distinct values in a node's buckets are returned
+to the node executing the query.
+The query node can then calculate the sum over
+the values that are unique across nodes,
+after eliminating duplicate values that come from separate nodes.
+</p>
+
+<p>
+The <code>COUNT</code> function returns the quantity of values in the set
+formed by the selected expression.
+For example, to return the quantity of employees who have a
+positive sales amount:
+</p>
+<pre>
+SELECT count(e.sales) FROM /employees e WHERE e.sales > 0.0
+</pre>
+<p>
+The <code>COUNT</code> function where the DISTINCT modifier is applied
+returns the quantity of unique (distinct) values in the set
+formed by the selected expression.
+</p>
+</div>
+
+<div style="background-color:lightyellow;">
+<h2>(Experimental Feature) GROUP BY Extension for Aggregate Functions</h2>
+
+<p>
+<code>GROUP BY</code> is required
+when aggregate functions are used in combination
+with other selected items.
+It permits ordering.
+For example,
+</p>
+
+<pre>
+SELECT ID, MAX(e.sales) FROM /employees e GROUP BY ID
+</pre>
+
+</div>
http://git-wip-us.apache.org/repos/asf/incubator-geode/blob/e1ffcd10/developing/querying_basics/restrictions_and_unsupported_features.html.md.erb
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diff --git a/developing/querying_basics/restrictions_and_unsupported_features.html.md.erb b/developing/querying_basics/restrictions_and_unsupported_features.html.md.erb
index 31a49b6..baac020 100644
--- a/developing/querying_basics/restrictions_and_unsupported_features.html.md.erb
+++ b/developing/querying_basics/restrictions_and_unsupported_features.html.md.erb
@@ -4,7 +4,6 @@ title: Query Language Restrictions and Unsupported Features
At a high level, Geode does not support the following querying features:
-- GROUPBY is not supported.
- Indexes targeted for joins across more than one region are not supported
- Static method invocations. For example, the following query is invalid:
@@ -12,10 +11,21 @@ At a high level, Geode does not support the following querying features:
SELECT DISTINCT * FROM /QueryRegion0 WHERE aDay = Day.Wednesday
```
-- Aggregate functions are not supported.
- You cannot create an index on fields using Set/List types (Collection types) that are not comparable. The OQL index implementation expects fields to be Comparable. To workaround this, you can create a custom Collection type that implements Comparable.
- ORDER BY is only supported with DISTINCT queries.
In addition, there are some specific limitations on partitioned region querying. See [Partitioned Region Query Restrictions](../query_additional/partitioned_region_query_restrictions.html#concept_5353476380D44CC1A7F586E5AE1CE7E8).
+<div style="background-color:lightyellow;">
+<h2> Features Supported on an Experimental Basis</h2>
+<p>
+These features are supported,
+but their experimental implementation may change:
+</p>
+
+<ul>
+<li> GROUP BY
+<li> The aggregate functions AVG, MIN, MAX, COUNT, SUM
+</ul>
+</div>