datafusion-examples/examples/parquet_sql.rs

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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 session context
    let ctx = SessionContext::new();

    let testdata = datafusion::test_util::parquet_test_data();

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

    // 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",
        )
        .await?;

    // print the results
    df.show().await?;

    Ok(())
}