go 通过sql操作mysql

go 通过sql操作mysql

go 通过sql操作mysql

亲测、2022/08/15 20:53 北京朝阳

@[toc]

前言

表格

结果

go代码

package main import ( "database/sql" "fmt" "time" _ "github.com/go-sql-driver/mysql" ) var db *sql.DB //全局变量client func initMySQL() (err error) { dsn := "root:123456@tcp(127.0.0.1:3306)/test" db, err = sql.Open("mysql", dsn) if err != nil { panic(err) } err = db.Ping() //检测是否连接成功 if err != nil { return } db.SetMaxOpenConns(200) //最大连接数 db.SetMaxIdleConns(10) //连接池里最大空闲连接数。必须要比maxOpenConns小 db.SetConnMaxLifetime(time.Second * 10) //最大存活保持时间 db.SetConnMaxIdleTime(time.Second * 10) //最大空闲保持时间 return } func main() { if err := initMySQL(); err != nil { fmt.Printf("connect to db failed,err:%v\n", err) } else { fmt.Println("connect to db success") } sqlStr := "SELECT id, name FROM sys_user WHERE id=?" var u user //非常重要：确保QueryRow之后调用Scan方法，否则持有的数据库链接不会被释放 err := db.QueryRow(sqlStr, 1).Scan(&u.id, &u.name) if err != nil { fmt.Printf("scan failed， err: %v\n", err) return } fmt.Printf("id:%d,name:%s,age:%d\n", u.id, u.name) defer db.Close() } //user结构体 type user struct { id int name string }

sql

database: test

CREATE TABLE `sys_user` ( `id` int(11) NOT NULL, `name` varchar(255) DEFAULT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1;

汇总-增删改查

结果：

package main import ( "database/sql" "fmt" "time" _ "github.com/go-sql-driver/mysql" ) var db *sql.DB func initMySQL() (err error) { dsn := "root:1234qwer@tcp(bj-cdb-mw08tjgs.sql.tencentcdb.com:60042)/test" db, err = sql.Open("mysql", dsn) if err != nil { panic(err) } err = db.Ping() if err != nil { return } db.SetMaxOpenConns(200) //最大连接数 db.SetMaxIdleConns(10) //连接池里最大空闲连接数。必须要比maxOpenConns小 db.SetConnMaxLifetime(time.Second * 10) //最大存活保持时间 db.SetConnMaxIdleTime(time.Second * 10) //最大空闲保持时间 return } func main() { if err := initMySQL(); err != nil { fmt.Printf("connect to db failed,err:%v\n", err) } else { fmt.Println("connect to db success") } select_one() queryMultiRowDemo() insertRowDemo() updateRowDemo() deleteRowDemo() defer db.Close() } type user struct { id int // age int name string } //查询 func select_one() { sqlStr := "SELECT id, name FROM sys_user WHERE id=?" var u user //非常重要：确保QueryRow之后调用Scan方法，否则持有的数据库链接不会被释放 err := db.QueryRow(sqlStr, 1).Scan(&u.id, &u.name) if err != nil { fmt.Printf("scan failed， err: %v\n", err) return } fmt.Printf("id:%d,name:%s\n", u.id, u.name) } // 查询多条数据示例 func queryMultiRowDemo() { sqlStr := "SELECT id,name FROM sys_user WHERE id>?" var u user rows, err := db.Query(sqlStr, 0) if err != nil { fmt.Printf("query failed, err:%v\n", err) return } //非常重要，关闭rows释放持有的数据库链接 defer rows.Close() for rows.Next() { err := rows.Scan(&u.id, &u.name) if err != nil { fmt.Printf("scan failed, err: %v\n", err) return } fmt.Printf("id:%d,name:%s\n", u.id, u.name) } } //插入数据 func insertRowDemo() { sqlStr := "INSERT INTO sys_user(id,name) VALUES(?,?)" ret, err := db.Exec(sqlStr, 23, "javapub") if err != nil { fmt.Printf("insert failed, err:%v\n", err) return } var theID int64 theID, err = ret.LastInsertId() if err != nil { fmt.Printf("get lastinsert ID failed,err:%v\n", err) return } fmt.Printf("insert success, the id is %d\n", theID) } //更新数据 func updateRowDemo() { sqlStr := "UPDATE sys_user SET name=? WHERE id=?" ret, err := db.Exec(sqlStr, "i love javapub", 23) if err != nil { fmt.Printf("updated failed,err:%v\n", err) return } var n int64 n, err = ret.RowsAffected() if err != nil { fmt.Printf("get rowsAffected failed,err:%v\b", err) return } fmt.Printf("updated success, the rows affected is %d\n", n) } //删除数据 func deleteRowDemo() { sqlStr := "DELETE FROM sys_user WHERE id=?" ret, err := db.Exec(sqlStr, 1) if err != nil { fmt.Printf("delete failed,err:%v\n", err) return } var n int64 n, err = ret.RowsAffected() if err != nil { fmt.Printf("get RowsAffected failed, err:%v\n", err) return } fmt.Printf("delete success, affected rows:%d\n", n) }

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