How to export data from MySQL database using Go language

In the process of software development, we often need to import and export data. In MySQL database, data export is a very common requirement. It allows us to export data in the database to other systems for analysis and processing. This article introduces how to export data from MySQL database using Go language.

1. Install Go language and MySQL driver

First, you need to install Go language and MySQL driver. If you have not installed the Go language, you can download and install it from the official website. After the installation is complete, you need to install the MySQL driver. In Go, there are many MySQL drivers to choose from. This article uses the go-sql-driver/mysql driver. You can install this driver using the following command:

go get github.com/go-sql-driver/mysql

2. Create a MySQL connection

To connect to a MySQL database, you need to specify the database address, username and password. In Go, we use the database/sql package to connect to MySQL. This package provides a set of functions and methods for connecting to MySQL. Here is a complete example of connecting to a MySQL database:

import (

"database/sql"
_ "github.com/go-sql-driver/mysql"

)

func main() {

db, err:= sql.Open("mysql", "username:password@tcp(127.0.0.1:3306)/database_name")
if err != nil {
    panic(err.Error())
}
defer db.Close()

}

3. Writing SQL query statements

In MySQL, to export data, you need to write a SELECT statement. This statement should return the data you want to export. In Go, we can use the Query method in the database/sql package to execute SQL query statements and return results. The following is an example of a simple SELECT query:

rows, err := db.Query("SELECT * FROM users")

4. Read query results

After executing the query, you need to read the query results. In Go, you can use the rows.Scan method to read the results of each row. You can then save these results to a file or elsewhere. The following is an example of reading query results:

for rows.Next() {

var name string
var age int
err = rows.Scan(&name, &age)
if err != nil {
    panic(err.Error())
}
fmt.Printf("Name: %s Age: %d

", name, age)
}

5. will Save query results to file

After reading the query results, you need to save the results to a file. In Go, you can use the os package and bufio package to write to the file. The following is a Example of saving query results to a CSV file:

file, err := os.Create("output.csv")
if err != nil {

panic(err.Error())

}
defer file.Close()

writer := csv.NewWriter(bufio.NewWriter(file))

for rows.Next() {

var name string
var age int
err = rows.Scan(&name, &age)
if err != nil {
    panic(err.Error())
}
err = writer.Write([]string{name, strconv.Itoa(age)})
if err != nil {
    panic(err.Error())
}

}

writer.Flush()

This will create a file named output.csv in the current directory and write the query results into the file.

Conclusion

Go language is a very popular programming language, which is efficient, simple and concurrency. This article introduces the method of using Go language to export data from MySQL database. We connect to the MySQL database and write SQL queries statement, the steps of reading the query results and saving the results to a file to achieve this goal. I hope this article can give you a better understanding of how to use the Go language to handle data export in a MySQL database.

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