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https://issues.apache.org/jira/browse/FLINK-3640?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15235285#comment-15235285
]
ASF GitHub Bot commented on FLINK-3640:
---------------------------------------
Github user fhueske commented on a diff in the pull request:
https://github.com/apache/flink/pull/1867#discussion_r59224646
--- Diff: docs/apis/batch/libs/table.md ---
@@ -408,3 +428,132 @@ Here, `literal` is a valid Java literal and `field
reference` specifies a column
column names follow Java identifier syntax.
Only the types `LONG` and `STRING` can be casted to `DATE` and vice versa.
A `LONG` casted to `DATE` must be a milliseconds timestamp. A `STRING` casted
to `DATE` must have the format "`yyyy-MM-dd HH:mm:ss.SSS`", "`yyyy-MM-dd`",
"`HH:mm:ss`", or a milliseconds timestamp. By default, all timestamps refer to
the UTC timezone beginning from January 1, 1970, 00:00:00 in milliseconds.
+
+{% top %}
+
+SQL
+----
+The Table API also supports embedded SQL queries.
+In order to use a `Table` or `DataSet` in a SQL query, it has to be
registered in the `TableEnvironment`, using a unique name.
+A registered `Table` can be retrieved back from the `TableEnvironment`
using the `scan` method:
+
+<div class="codetabs" markdown="1">
+<div data-lang="java" markdown="1">
+{% highlight java %}
+ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();
+// create a Table environment
+TableEnvironment tableEnv = new TableEnvironment();
+// reset the translation context: this will erase existing registered
Tables
+TranslationContext.reset();
+// read a DataSet from an external source
+DataSet<Tuple2<Integer, Long>> ds = env.readTextFile(...);
+// register the DataSet under the name "MyTable"
+tableEnv.registerDataSet("MyTable", ds);
+// retrieve "MyTable" into a new Table
+Table t = tableEnv.scan("MyTable");
+{% endhighlight %}
+</div>
+
+<div data-lang="scala" markdown="1">
+{% highlight scala %}
+val env = ExecutionEnvironment.getExecutionEnvironment
+// create a Table environment
+val tEnv = new TableEnvironment
+// reset the translation context: this will erase existing registered
Tables
+TranslationContext.reset()
+// read a DataSet from an external source
+val ds = env.readTextFile(...)
+// register the DataSet under the name "MyTable"
+tEnv.registerDataSet("MyTable", ds)
+// retrieve "MyTable" into a new Table
+val t = tEnv.scan("MyTable")
+{% endhighlight %}
+</div>
+</div>
+
+*Note: Table names are not allowed to follow the `^_DataSetTable_[0-9]+`
pattern, as this is reserved for internal use only.*
+
+When registering a `DataSet`, one can also give names to the `Table`
columns. For example, if "MyTable" has three columns, `user`, `product`, and
`order`, we can give them names upon registering the `DataSet` as shown below:
+
+<div class="codetabs" markdown="1">
+<div data-lang="java" markdown="1">
+{% highlight java %}
+// register the DataSet under the name "MyTable" with columns user,
product, and order
+tableEnv.registerDataSet("MyTable", ds, "user, product, order");
--- End diff --
Java examples use `tableEnv`, Scala examples use `tEnv`. Is that on purpose?
> Add support for SQL queries in DataSet programs
> -----------------------------------------------
>
> Key: FLINK-3640
> URL: https://issues.apache.org/jira/browse/FLINK-3640
> Project: Flink
> Issue Type: New Feature
> Components: Table API
> Affects Versions: 1.1.0
> Reporter: Vasia Kalavri
> Assignee: Vasia Kalavri
>
> This issue covers the task of supporting SQL queries embedded in DataSet
> programs. In this mode, the input and output of a SQL query is a Table. For
> this issue, we need to make the following additions to the Table API:
> - add a {{tEnv.sql(query: String): Table}} method for converting a query
> result into a Table
> - integrate Calcite's SQL parser into the batch Table API translation process.
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