gormExample/raw.go

package gormExample

import "log"

// 原生查询测试
func RawSelect() {
	// 结果类型
	type Result struct {
		ID           uint
		Subject      string
		Likes, Views int
	}
	var rs []Result

	// SQL
	sql := "SELECT `id`, `subject`, `likes`, `views` FROM `msb_content` WHERE `likes` > ? ORDER BY `likes` DESC LIMIT ?"

	// 执行SQL，并扫描结果
	if err := DB.Raw(sql, 99, 12).Scan(&rs).Error; err != nil {
		log.Fatalln(err)
	}
	// [8.298ms] [rows:12] SELECT `id`, `subject`, `likes`, `views` FROM `msb_content` WHERE `likes` > 99 ORDER BY `likes` DESC LIMIT 12

	log.Println(rs)
}

// 执行类的SQL原生
func RawExec() {
	// SQL
	sql := "UPDATE `msb_content` SET `subject` = CONCAT(`subject`, '-new postfix') WHERE `id` BETWEEN ? AND ?"

	// 执行，获取结果
	result := DB.Exec(sql, 30, 40)
	if result.Error != nil {
		log.Fatalln(result.Error)
	}
	// [13.369ms] [rows:10] UPDATE `msb_content` SET `subject` = CONCAT(`subject`, '-new postfix') WHERE `id` BETWEEN 30 AND 40

	log.Println(result.RowsAffected)

}

// sql.Row 或 sql.Rows 类型的结果处理
func RowAndRows() {
	// sql
	sql := "SELECT `id`, `subject`, `likes`, `views` FROM `msb_content` WHERE `likes` > ? ORDER BY `likes` DESC LIMIT ?"

	// 执行，获取rows
	rows, err := DB.Raw(sql, 99, 12).Rows()
	if err != nil {
		log.Fatalln(err)
	}

	// 遍历rows
	for rows.Next() {
		// 扫描的列独立的变量
		//var id uint
		//var subject string
		//var likes, views int
		//rows.Scan(&id, &subject, &likes, &views)
		//log.Println(id, subject, likes, views)

		// 扫描到整体结构体
		type Result struct {
			ID           uint
			Subject      string
			Likes, Views int
		}
		var r Result
		if err := DB.ScanRows(rows, &r); err != nil {
			log.Fatalln(err)
		}
		log.Println(r)
	}
}