wdick commented on a change in pull request #23362: [MINOR][DOCS]Document
subquery support for the `table` parameter
URL: https://github.com/apache/spark/pull/23362#discussion_r243597140
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File path: sql/core/src/main/scala/org/apache/spark/sql/DataFrameReader.scala
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@@ -235,6 +235,19 @@ class DataFrameReader private[sql](sparkSession:
SparkSession) extends Logging {
* Construct a `DataFrame` representing the database table accessible via
JDBC URL
* url named table and connection properties.
*
+ * The `table` parameter can be based on a derived table, which is generated
within the scope of
+ * a query FROM clause. For example, you could use this subquery as `table:
+ * {{{
+ * "(SELECT * FROM customers WHERE ...) AS tmp"
+ * }}}
+ *
+ * @param url JDBC database url of the form `jdbc:subprotocol:subname`.
+ * @param table Name of the table in the external database.
+ * @param properties JDBC database connection arguments, a list of arbitrary
string
+ * tag/value. Normally at least a "user" and
"password" property
+ * should be included. "fetchsize" can be used
to control the
+ * number of rows per fetch and "queryTimeout"
can be used to wait
+ * for a Statement object to execute to the
given number of seconds.
Review comment:
I will close the PR, so no need to fix it.
What does 'nit' mean?
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