3使用API JAVA在Spark SQL中进行左连接

import org.apache.spark.sql.Dataset;
import org.apache.spark.sql.Row;
import org.apache.spark.sql.SparkSession;
import static org.apache.spark.sql.functions.*;

SparkSession spark = SparkSession.builder()
        .appName("LeftJoinExample")
        .master("local")
        .getOrCreate();

Dataset<Row> dataset1 = spark.read().format("csv").option("header", "true").load("path/to/dataset1.csv");
Dataset<Row> dataset2 = spark.read().format("csv").option("header", "true").load("path/to/dataset2.csv");

Dataset<Row> leftJoinResult = dataset1.join(dataset2, dataset1.col("joinColumn").equalTo(dataset2.col("joinColumn")), "left");

leftJoinResult.show();