GO DB.QueryContext用法及代码示例

package main

import (
    "context"
    "database/sql"
    "fmt"
    "log"
    "strings"
)

var (
    ctx context.Context
    db  *sql.DB
)

func main() {
    age := 27
    rows, err := db.QueryContext(ctx, "SELECT name FROM users WHERE age=?", age)
    if err != nil {
        log.Fatal(err)
    }
    defer rows.Close()
    names := make([]string, 0)

    for rows.Next() {
        var name string
        if err := rows.Scan(&name); err != nil {
            // Check for a scan error.
            // Query rows will be closed with defer.
            log.Fatal(err)
        }
        names = append(names, name)
    }
    // If the database is being written to ensure to check for Close
    // errors that may be returned from the driver. The query may
    // encounter an auto-commit error and be forced to rollback changes.
    rerr := rows.Close()
    if rerr != nil {
        log.Fatal(rerr)
    }

    // Rows.Err will report the last error encountered by Rows.Scan.
    if err := rows.Err(); err != nil {
        log.Fatal(err)
    }
    fmt.Printf("%s are %d years old", strings.Join(names, ", "), age)
}