使用 database/sql 包查询数据库并获取返回行数

package main

import (
    "database/sql"
    "fmt"
    _ "github.com/go-sql-driver/mysql" // 导入 MySQL 驱动，根据实际数据库选择
    "log"
)

// execQuery 执行 SQL 查询并返回结果集和执行状态
func execQuery(db *sql.DB, SQL string, args ...interface{}) (rows *sql.Rows, isSucceed bool) {
    rows, err := db.Query(SQL, args...)
    if err != nil {
        log.Printf("Query failed: %v", err)
        return nil, false
    }
    return rows, true
}

func main() {
    // 数据库连接信息，根据实际情况修改
    dbUser := "user"
    dbPass := "password"
    dbHost := "localhost"
    dbPort := "3306"
    dbName := "database_name"

    // 构建连接字符串
    dsn := fmt.Sprintf("%s:%s@tcp(%s:%s)/%s", dbUser, dbPass, dbHost, dbPort, dbName)

    // 连接数据库
    db, err := sql.Open("mysql", dsn)
    if err != nil {
        log.Fatalf("Failed to connect to database: %v", err)
    }
    defer db.Close()

    // 测试连接
    if err := db.Ping(); err != nil {
        log.Fatalf("Failed to ping database: %v", err)
    }

    // 示例 SQL 查询
    query := "SELECT id, name, age FROM test WHERE id = ?"
    targetID := "123"

    // 执行查询
    rows, isSucceed := execQuery(db, query, targetID)
    if !isSucceed {
        fmt.Println("Query failed")
        return
    }
    defer rows.Close()

    // 处理查询结果
    var id, age int
    var name string
    rowCount := 0

    for rows.Next() {
        err := rows.Scan(&id, &name, &age)
        if err != nil {
            log.Printf("Failed to scan row: %v", err)
            continue
        }

        if rowCount == 0 {
            fmt.Printf("First row: id=%d, name=%s, age=%d\n", id, name, age)
        }
        rowCount++
    }

    if err := rows.Err(); err != nil {
        log.Printf("Error during rows iteration: %v", err)
    }

    // 判断行数
    if rowCount == 0 {
        fmt.Println("No rows returned")
    } else if rowCount == 1 {
        fmt.Println("One row returned")
    } else {
        fmt.Printf("%d rows returned\n", rowCount)
    }
}