Querying Parquet files

[marcboeker]

Querying Parquet files

[marcboeker]

Have you tried running INSTALL parquet; LOAD parquet beforehand like in https://github.com/marcboeker/go-duckdb/blob/master/duckdb_test.go#L910-L912?

[peterinfra]

Thanks for the pointer. I am able to follow along the example from the JSON extension and use it for parquet.

import (
	"context"
	"database/sql"
	"database/sql/driver"
	"fmt"
	"log"

	"github.com/marcboeker/go-duckdb"
)

var db *sql.DB

func check(args ...interface{}) {
	err := args[len(args)-1]
	if err != nil {
		panic(err)
	}
}

func loadParquet(execer driver.ExecerContext) error {
	bootQueries := []string{
		"INSTALL 'parquet'",
		"LOAD 'parquet'",
	}

	for _, qry := range bootQueries {
		_, err := execer.ExecContext(context.TODO(), qry, nil)
		if err != nil {
			return err
		}
	}
	return nil
}

type data struct {
	c int64
}

func main() {
	connector, err := duckdb.NewConnector("", loadParquet)
	if err != nil {
		fmt.Println("Failed to load Parquet")
		log.Fatal(err)
	}

	db := sql.OpenDB(connector)
	if err != nil {
		log.Fatal(err)
	}
	defer db.Close()
	check(db.Ping())
	rows, err := db.Query(`select count(*) as c from read_parquet('my.parquet');`)
	check(err)
	defer rows.Close()
	for rows.Next() {
		c := new(data)
		err := rows.Scan(&c.c)
		if err != nil {
			log.Fatal(err)
		}
		log.Printf("Count = %d", c.c)
		fmt.Println(c.c)
	}

}