SQL操作：RightOuterJoin (RightOuterJoinBatchOp)

Java 类名：com.alibaba.alink.operator.batch.sql.RightOuterJoinBatchOp
Python 类名：RightOuterJoinBatchOp

功能介绍

对批式数据进行sql的RIGHT OUTER JOIN操作。

参数说明

| 名称 | 中文名称 | 描述 | 类型 | 是否必须？ | 取值范围 | 默认值 | | —- | —- | —- | —- | —- | —- | —- |

| joinPredicate | where语句 | where语句 | String | ✓ | | |

| selectClause | select语句 | select语句 | String | ✓ | | |

| type | join类型 | join类型: “join”, “leftOuterJoin”, “rightOuterJoin” 或 “fullOuterJoin” | String | | “JOIN”, “LEFTOUTERJOIN”, “RIGHTOUTERJOIN”, “FULLOUTERJOIN” | “JOIN” |

代码示例

Python 代码

from pyalink.alink import *
import pandas as pd
useLocalEnv(1)
df1 = pd.DataFrame([
    ['Ohio', 2000, 1.5],
    ['Ohio', 2001, 1.7],
    ['Ohio', 2002, 3.6],
    ['Nevada', 2001, 2.4],
    ['Nevada', 2002, 2.9],
    ['Nevada', 2003, 3.2]
])
df2 = pd.DataFrame([
    ['Nevada', 2001, 2.4],
    ['Nevada', 2003, 3.2]
])
batch_data1 = BatchOperator.fromDataframe(df1, schemaStr='f1 string, f2 bigint, f3 double')
batch_data2 = BatchOperator.fromDataframe(df2, schemaStr='f1 string, f2 bigint, f3 double')
op = RightOuterJoinBatchOp().setJoinPredicate("a.f1=b.f1").setSelectClause("a.f1, a.f2, a.f3")
op.linkFrom(batch_data2, batch_data1).print()

Java 代码

import com.alibaba.alink.operator.batch.BatchOperator;
import com.alibaba.alink.operator.batch.source.MemSourceBatchOp;
import com.alibaba.alink.operator.batch.sql.RightOuterJoinBatchOp;
import org.junit.Test;
public class RightOuterJoinBatchOpTest {
    @Test
    public void testRightOuterJoinBatchOp() throws Exception {
        List <Row> df1 = Arrays.asList(
            Row.of("Ohio", 2000, 1.5),
            Row.of("Ohio", 2001, 1.7),
            Row.of("Ohio", 2002, 3.6),
            Row.of("Nevada", 2001, 2.4),
            Row.of("Nevada", 2002, 2.9),
            Row.of("Nevada", 2003, 3.2)
        );
        List <Row> df2 = Arrays.asList(
            Row.of("Nevada", 2001, 2.4),
            Row.of("Nevada", 2003, 3.2)
        );
        BatchOperator <?> data1 = new MemSourceBatchOp(df1, "f1 string, f2 int, f3 double");
        BatchOperator <?> data2 = new MemSourceBatchOp(df2, "f1 string, f2 int, f3 double");
        BatchOperator <?> joinOp = new RightOuterJoinBatchOp()
            .setJoinPredicate("a.f1=b.f1")
            .setSelectClause("a.f1, a.f2, a.f3");
        joinOp.linkFrom(data2, data1).print();
    }
}

运行结果

| f1 | f2 | f3 | | —- | —- | —- |

| Nevada | 2001 | 2.4000 |

| Nevada | 2001 | 2.4000 |

| Nevada | 2001 | 2.4000 |

| Nevada | 2003 | 3.2000 |

| Nevada | 2003 | 3.2000 |

| Nevada | 2003 | 3.2000 |

| null | null | null |

| null | null | null |

| null | null | null |