rust/datafusion/examples/parquet_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 (Parquet) and
/// fetching results
#[tokio::main]
async fn main() -> Result<()> {
    // create local execution context
    let mut ctx = ExecutionContext::new();

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

    // register parquet file with the execution context
    ctx.register_parquet(
        "alltypes_plain",
        &format!("{}/alltypes_plain.parquet", testdata),
    )?;

    // execute the query
    let df = ctx.sql(
        "SELECT int_col, double_col, CAST(date_string_col as VARCHAR) \
        FROM alltypes_plain \
        WHERE id > 1 AND tinyint_col < double_col",
    )?;
    let results = df.collect().await?;

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

    Ok(())
}