dynamic scan types #478

Author: kshvakov

examples/native/dynamic-scan-types/main.go

@@ -0,0 +1,60 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"log"
+	"reflect"
+
+	"github.com/ClickHouse/clickhouse-go/v2"
+)
+
+func example() error {
+	conn, err := clickhouse.Open(&clickhouse.Options{
+		Addr: []string{"127.0.0.1:9000"},
+		Auth: clickhouse.Auth{
+			Database: "default",
+			Username: "default",
+			Password: "",
+		},
+	})
+	if err != nil {
+		return err
+	}
+	const query = `
+	SELECT
+		   1     AS Col1
+		, 'Text' AS Col2
+	`
+	rows, err := conn.Query(context.TODO(), query)
+	if err != nil {
+		return err
+	}
+	var (
+		columnTypes = rows.ColumnTypes()
+		vars        = make([]interface{}, len(columnTypes))
+	)
+	for i := range columnTypes {
+		value := reflect.New(columnTypes[i].ScanType()).Interface()
+		vars[i] = value
+	}
+	for rows.Next() {
+		if err := rows.Scan(vars...); err != nil {
+			return err
+		}
+		for _, v := range vars {
+			switch v := v.(type) {
+			case *string:
+				fmt.Println(*v)
+			case *uint8:
+				fmt.Println(*v)
+			}
+		}
+	}
+	return nil
+}
+func main() {
+	if err := example(); err != nil {
+		log.Fatal(err)
+	}
+}