在 InfluxQL 中使用参数化查询

import (
    "context"
    "fmt"
    "io"
    "os"
    "text/tabwriter"
    "time"
    "github.com/apache/arrow/go/v14/arrow"
    "github.com/InfluxCommunity/influxdb3-go/influxdb3"
)

func Query(query string, parameters influxdb3.QueryParameters,
 options influxdb3.QueryOptions) error {
    url := os.Getenv("INFLUX_HOST")
    token := os.Getenv("INFLUX_TOKEN")
    database := os.Getenv("INFLUX_DATABASE")

    // Instantiate the influxdb3 client.
    client, err := influxdb3.New(influxdb3.ClientConfig{
        Host:     url,
        Token:    token,
        Database: database,
    })

    if err != nil {
        panic(err)
    }

    // Ensure the client is closed after the Query function finishes.
    defer func(client *influxdb3.Client) {
        err := client.Close()
        if err != nil {
            panic(err)
        }
    }(client)

    // Call the client's QueryWithParameters function.
    // Provide the query, parameters, and the InfluxQL QueryType option.
    iterator, err := client.QueryWithParameters(context.Background(), query,
    parameters, influxdb3.WithQueryType(options.QueryType))

    // Create a buffer for storing rows as you process them.
    w := tabwriter.NewWriter(io.Discard, 4, 4, 1, ' ', 0)
    w.Init(os.Stdout, 0, 8, 0, '\t', 0)

    fmt.Fprintf(w, "time\troom\tco\thum\ttemp\n")

    // Format and write each row to the buffer.
    // Process each row as key-value pairs.
    for iterator.Next() {
        row := iterator.Value()
        // Use Go arrow and time packages to format unix timestamp
        // as a time with timezone layout (RFC3339 format)
        time := (row["time"].(arrow.Timestamp)).
                ToTime(arrow.Nanosecond).Format(time.RFC3339)

        fmt.Fprintf(w, "%s\t%s\t%d\t%.1f\t%.1f\n",
            time, row["room"], row["co"], row["hum"], row["temp"])
    }
    w.Flush()

    return nil
}

func main() {
    // Use the $placeholder syntax in a query to reference parameter placeholders
    // for input data.
    // The following InfluxQL query contains the placeholders $room and $min_temp.
    query := `
        SELECT *
        FROM home
        WHERE time > now() - 7d
        AND temp >= $min_temp
        AND room = $room`

    // Define a QueryParameters struct--a map of placeholder names to input values.
    parameters := influxdb3.QueryParameters{
        "room": "Kitchen",
        "min_temp": 20.0,
    }

    Query(query, parameters, influxdb3.QueryOptions{
        QueryType: influxdb3.InfluxQL,
    })
}