BatchTableEnvironment can be used to create a
Table from a DataSet.See: Description
BatchTableEnvironment can be used to create a
Table from a DataSet.
Equivalently, a StreamTableEnvironment can be used
to create a Table from a DataStream.
Tables can be used to perform SQL-like queries on data. Please have a look at Table to see which operations are supported and how query strings are
written.
Example:
ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();
BatchTableEnvironment tEnv = TableEnvironment.getTableEnvironment(env);
DataSet<WC> input = env.fromElements(
new WC("Hello", 1),
new WC("Ciao", 1),
new WC("Hello", 1));
Table table = tEnv.fromDataSet(input);
Table filtered = table
.groupBy("word")
.select("word.count as count, word")
.filter("count = 2");
DataSet<WC> result = tEnv.toDataSet(filtered, WC.class);
result.print();
As seen above, a Table can be converted back to the
underlying API representation using BatchTableEnvironment.toDataSet(Table, java.lang.Class),
StreamTableEnvironment.toAppendStream(Table,
java.lang.Class)}, or StreamTableEnvironment.toRetractStream(Table,
java.lang.Class)}.
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