Function dataframe_example

datafusion-examples/examples/dataframe/dataframe.rs:61–76

This example demonstrates using DataFusion's DataFrame API # Reading from different formats [read_parquet]: execute queries against parquet files [read_csv]: execute queries against csv files [read_memory]: execute queries against in-memory arrow data [read_memory_macro]: execute queries against in-memory arrow data using macro # Writing out to local storage The following examples demonstrate

()

/// * [where_in_subquery]: execute a subquery with an IN clause
/// * [where_exist_subquery]: execute a subquery with an EXISTS clause
pub async fn dataframe_example() -> Result<()> {
    env_logger::init();
    // The SessionContext is the main high level API for interacting with DataFusion
    let ctx = SessionContext::new();
    read_parquet(&ctx).await?;
    read_csv(&ctx).await?;
    read_memory(&ctx).await?;
    read_memory_macro().await?;
    write_out(&ctx).await?;
    register_cars_test_data("t1", &ctx).await?;
    register_cars_test_data("t2", &ctx).await?;
    where_scalar_subquery(&ctx).await?;
    where_in_subquery(&ctx).await?;
    where_exist_subquery(&ctx).await?;
    Ok(())
}

/// Use DataFrame API to
/// 1. Read parquet files,