rust/datafusion/examples/csv_sql.rs

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//   http://www.apache.org/licenses/LICENSE-2.0
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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 (CSV) and
/// fetching results
#[tokio::main]
async fn main() -> Result<()> {
    // create local execution context
    let mut ctx = ExecutionContext::new();

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

    // register csv file with the execution context
    ctx.register_csv(
        "aggregate_test_100",
        &format!("{}/csv/aggregate_test_100.csv", testdata),
        CsvReadOptions::new(),
    )?;

    // execute the query
    let df = ctx.sql(
        "SELECT c1, MIN(c12), MAX(c12) \
        FROM aggregate_test_100 \
        WHERE c11 > 0.1 AND c11 < 0.9 \
        GROUP BY c1",
    )?;
    let results = df.collect().await?;

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

    Ok(())
}