rust/datafusion/examples/dataframe.rs

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use arrow::util::pretty;

use datafusion::error::Result;
use datafusion::prelude::*;

/// This example demonstrates executing a simple query against an Arrow data source (Parquet) and
/// fetching results, using the DataFrame trait
#[tokio::main]
async fn main() -> Result<()> {
    // create local execution context
    let mut ctx = ExecutionContext::new();

    let testdata = arrow::util::test_util::parquet_test_data();

    let filename = &format!("{}/alltypes_plain.parquet", testdata);

    // define the query using the DataFrame trait
    let df = ctx
        .read_parquet(filename)?
        .select_columns(&["id", "bool_col", "timestamp_col"])?
        .filter(col("id").gt(lit(1)))?;

    // execute the query
    let results = df.collect().await?;

    // print the results
    pretty::print_batches(&results)?;

    Ok(())
}