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https://issues.apache.org/jira/browse/FLINK-6442?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16131995#comment-16131995
]
ASF GitHub Bot commented on FLINK-6442:
---------------------------------------
Github user lincoln-lil commented on a diff in the pull request:
https://github.com/apache/flink/pull/3829#discussion_r133921697
--- Diff:
flink-libraries/flink-table/src/main/scala/org/apache/flink/table/api/TableEnvironment.scala
---
@@ -502,26 +513,140 @@ abstract class TableEnvironment(val config:
TableConfig) {
* tEnv.sql(s"SELECT * FROM $table")
* }}}
*
- * @param query The SQL query to evaluate.
+ * @param sql The SQL string to evaluate.
* @return The result of the query as Table.
*/
- def sql(query: String): Table = {
+ @deprecated
+ def sql(sql: String): Table = {
val planner = new FlinkPlannerImpl(getFrameworkConfig, getPlanner,
getTypeFactory)
// parse the sql query
- val parsed = planner.parse(query)
+ val parsed = planner.parse(sql)
// validate the sql query
val validated = planner.validate(parsed)
// transform to a relational tree
val relational = planner.rel(validated)
-
new Table(this, LogicalRelNode(relational.rel))
}
/**
+ * Evaluates a SQL Select query on registered tables and retrieves the
result as a
+ * [[Table]].
+ *
+ * All tables referenced by the query must be registered in the
TableEnvironment. But
+ * [[Table.toString]] will automatically register an unique table name
and return the
+ * table name. So it allows to call SQL directly on tables like this:
+ *
+ * {{{
+ * val table: Table = ...
+ * // the table is not registered to the table environment
+ * tEnv.sqlSelect(s"SELECT * FROM $table")
+ * }}}
+ *
+ * @param sql The SQL string to evaluate.
+ * @return The result of the query as Table or null of the DML insert
operation.
+ */
+ def sqlQuery(sql: String): Table = {
+ val planner = new FlinkPlannerImpl(getFrameworkConfig, getPlanner,
getTypeFactory)
+ // parse the sql query
+ val parsed = planner.parse(sql)
+ if (null != parsed && parsed.getKind.belongsTo(SqlKind.QUERY)) {
+ // validate the sql query
+ val validated = planner.validate(parsed)
+ // transform to a relational tree
+ val relational = planner.rel(validated)
+ new Table(this, LogicalRelNode(relational.rel))
+ } else {
+ throw new TableException(
+ "Unsupported sql query! sqlQuery Only accept SELECT, UNION,
INTERSECT, EXCEPT, VALUES, " +
--- End diff --
SqlParser.parseStmt() actually call the SqlParser.parseQuery, so they're
the same. Could not help us to distinguish the sql type, so use SqlKind here,
SqlKind.QUERY consists of: SELECT, EXCEPT, INTERSECT, UNION, VALUES, ORDER_BY,
EXPLICIT_TABLE.
> Extend TableAPI Support Sink Table Registration and ‘insert into’ Clause in
> SQL
> -------------------------------------------------------------------------------
>
> Key: FLINK-6442
> URL: https://issues.apache.org/jira/browse/FLINK-6442
> Project: Flink
> Issue Type: New Feature
> Components: Table API & SQL
> Reporter: lincoln.lee
> Assignee: lincoln.lee
> Priority: Minor
>
> Currently in TableAPI there’s only registration method for source table,
> when we use SQL writing a streaming job, we should add additional part for
> the sink, like TableAPI does:
> {code}
> val sqlQuery = "SELECT * FROM MyTable WHERE _1 = 3"
> val t = StreamTestData.getSmall3TupleDataStream(env)
> tEnv.registerDataStream("MyTable", t)
> // one way: invoke tableAPI’s writeToSink method directly
> val result = tEnv.sql(sqlQuery)
> result.writeToSink(new YourStreamSink)
> // another way: convert to datastream first and then invoke addSink
> val result = tEnv.sql(sqlQuery).toDataStream[Row]
> result.addSink(new StreamITCase.StringSink)
> {code}
> From the api we can see the sink table always be a derived table because its
> 'schema' is inferred from the result type of upstream query.
> Compare to traditional RDBMS which support DML syntax, a query with a target
> output could be written like this:
> {code}
> insert into table target_table_name
> [(column_name [ ,...n ])]
> query
> {code}
> The equivalent form of the example above is as follows:
> {code}
> tEnv.registerTableSink("targetTable", new YourSink)
> val sql = "INSERT INTO targetTable SELECT a, b, c FROM sourceTable"
> val result = tEnv.sql(sql)
> {code}
> It is supported by Calcite’s grammar:
> {code}
> insert:( INSERT | UPSERT ) INTO tablePrimary
> [ '(' column [, column ]* ')' ]
> query
> {code}
> I'd like to extend Flink TableAPI to support such feature. see design doc:
> https://goo.gl/n3phK5
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