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This article mainly explains the "query conversion method of flinksql table". The content of the explanation in the article is simple and clear, and it is easy to learn and understand. Please follow the editor's train of thought to study and learn the query transformation method of flinksql table.

Package com.jd.data;import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;import org.apache.flink.table.api.DataTypes;import org.apache.flink.table.api.Table;import org.apache.flink.table.api.bridge.java.StreamTableEnvironment;import org.apache.flink.table.descriptors.FileSystem;import org.apache.flink.table.descriptors.OldCsv;import org.apache.flink.table.descriptors.Schema;import org.apache.flink.types.Row;import scala.Tuple3 Import static org.apache.flink.table.api.Expressions.$;public class TableAipDemo03 {public static void main (String [] args) throws Exception {StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment (); env.setParallelism (1); / / 1. Creation table execution StreamTableEnvironment tableEnv = StreamTableEnvironment.create (env); String path = "/ Users/liuhaijing/Desktop/flinktestword/aaa.txt" TableEnv.connect (new FileSystem (). Path (path)) .withFormat (new OldCsv ()) / defines the formatting method .withSchema (new Schema (). Field ("a", DataTypes.STRING ()) / / defines the structure of the table .field ("b", DataTypes.STRING ()) .field ("c") DataTypes.STRING ()) .createTemporaryTable ("xxx") / / query and transformation of tables Table xxx = tableEnv.from ("xxx"); / / simple query Table select = xxx.select ("a, b"). Filter ($("a"). IsEqual ("a"); Table select2 = select.groupBy ($("a")) .select ($("a"), $("a"). Count (). As ("count")) Select2.printSchema (); / / output result in a revocable manner will be preceded by a column of boolean true indicating that this time shall prevail, and false shall be invalid tableEnv.toRetractStream (select2, Row.class). Print (); env.execute ("job") }} Thank you for your reading, the above is the content of "query conversion method of flinksql table". After the study of this article, I believe you have a deeper understanding of the query conversion method of flinksql table, and the specific use needs to be verified in practice. Here is, the editor will push for you more related knowledge points of the article, welcome to follow!

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