Function with_column_join_same_columns

datafusion/core/tests/dataframe/mod.rs:1950–2030

()

// The join operation outputs two identical column names, but they belong to different relations.
#[tokio::test]
async fn with_column_join_same_columns() -> Result<()> {
    let df = test_table().await?.select_columns(&["c1"])?;
    let ctx = SessionContext::new();

    let table = df.into_view();
    ctx.register_table("t1", table.clone())?;
    ctx.register_table("t2", table)?;
    let df = ctx
        .table("t1")
        .await?
        .join(
            ctx.table("t2").await?,
            JoinType::Inner,
            &["c1"],
            &["c1"],
            None,
        )?
        .sort(vec![
            // make the test deterministic
            col("t1.c1").sort(true, true),
        ])?
        .limit(0, Some(1))?;

    let df_results = df.clone().collect().await?;
    assert_snapshot!(
        batches_to_sort_string(&df_results),
        @r"
    +----+----+
    | c1 | c1 |
    +----+----+
    | a  | a  |
    +----+----+
    "
    );

    let df_with_column = df.clone().with_column("new_column", lit(true))?;

    assert_snapshot!(
        df_with_column.logical_plan(),
        @r"
    Projection: t1.c1, t2.c1, Boolean(true) AS new_column
      Limit: skip=0, fetch=1
        Sort: t1.c1 ASC NULLS FIRST
          Inner Join: t1.c1 = t2.c1
            SubqueryAlias: t1
              Projection: aggregate_test_100.c1
                TableScan: aggregate_test_100
            SubqueryAlias: t2
              Projection: aggregate_test_100.c1
                TableScan: aggregate_test_100
    "
    );

    assert_snapshot!(
        df_with_column.clone().into_optimized_plan().unwrap(),
        @r"
    Projection: t1.c1, t2.c1, Boolean(true) AS new_column
      Sort: t1.c1 ASC NULLS FIRST, fetch=1