Node.js MySQL DELETE

Node.js MySQL delete records

The Node.js MySQL delete query can help you delete one or more records from the table based on filtering conditions.

• MySQL delete some records based on filter

• MySQL delete all records from table

Node.js MySQL – Delete records from table based on conditions

Execute a DELETE FROM query on the specified table when a filter is applied to one or more properties of the records in the table.

Content of the student table before deleting records

mysql> select　*　from students;　
+---------------+--------+-------+
| name | rollno | marks |
+---------------+--------+-------+
| John |　1　|　74　|
| Arjun |　2　|　74　|
| Prasanth |　3　|　77　|
| Adarsh |　4　|　78　|
| Raja |　5　|　94　|
| Sai |　6　|　84　|
| Ross |　7　|　54　|
| Monica Gellar |　8　|　86　|
| Lee |　9　|　98　|
| Bruce Wane |　10　|　92　|
| Sukumar |　11　|　99　|
| Anisha |　12　|　95　|
| Miley |　13　|　85　|
| Jobin |　14　|　87　|
| Jack |　16　|　82　|
| Priya |　17　|　88　|
+---------------+--------+-------+
16　rows in set (0.00 sec)

　//　Import the mysql module　
　var mysql = require('mysql');　
　
　//　Create a connection variable with the required details　
　var con = mysql.createConnection({　
　　host: "localhost",　//　The IP address of the server running mysql　
　　user: "arjun",　//　MySQL database username
　　password: "password",　//　The corresponding password
　　database: "studentsDB"　//　Use the specified database
　});　
　
　//　Connect to the database.　
　con.connect(function (err) {　
　　if (err) throw err;　
　　//　If the connection is successful　
　　con.query("DELETE FROM students WHERE rollno>10" function (err, result, fields) {　
　　　　//　If any errors occur during the execution of the above query, throw an error　
　　　　if (err) throw err;　
　　　　//　If there are no errors, you will get the result　
　　　　console.log(result);　
　　});　
　});

Run deleteRecordsFiltered.js-Terminal Output

arjun@arjun-VPCEH26EN:~/workspace/nodejs$ node deleteRecordsFiltered.js　
OkPacket {　
　　fieldCount: 0,　
　　affectedRows:　6,　
　　insertId: 0,　
　　serverStatus:　34,　
　　warningCount: 0,　
　　message: '',　
　　protocol41: true,　
　　changedRows: 0 }

Observation results, affected behaviors6, which means that6records.

The following records remain after executing the MySQL DELETE FROM query on the student table.

Deleted student table content

mysql> select　*　from students;　
+---------------+--------+-------+
| name | rollno | marks |
+---------------+--------+-------+
| John |　1　|　74　|
| Arjun |　2　|　74　|
| Prasanth |　3　|　77　|
| Adarsh |　4　|　78　|
| Raja |　5　|　94　|
| Sai |　6　|　84　|
| Ross |　7　|　54　|
| Monica Gellar |　8　|　86　|
| Lee |　9　|　98　|
| Bruce Wane |　10　|　92　|
+---------------+--------+-------+
10　rows in set (0.00 sec)

Node.js MySQL – Delete All Records from Table

//　Import the mysql module
var mysql = require('mysql');　
　
//　Create a connection variable with the required details
var con = mysql.createConnection({　
　　host: "localhost",　//　The IP address of the server running mysql
　　user: "arjun",　//　MySQL database username
　　password: "password",　//　The corresponding password
　　database: "studentsDB"　//　Use the specified database
　});　
　
//　Connect to the database.
con.connect(function (err) {　
　　if (err) throw err;　
　　//　If the connection is successful
　　con.query("DELETE FROM students", function (err, result, fields) {　
　　　　//　If any errors occur during the execution of the above query, throw an error
　　　　if (err) throw err;　
　　　　//　If there are no errors, you will get the result
　　　　console.log(result);　
　　});　
　});

Run deleteRecordsAll.js-Terminal Output

arjun@arjun-VPCEH26EN:~/workspace/nodejs$ node deleteRecordsAll.js　
OkPacket {　
　　fieldCount: 0,　
　　affectedRows:　10,　
　　insertId: 0,　
　　serverStatus:　34,　
　　warningCount: 0,　
　　message: '',　
　　protocol41: true,　
　　changedRows: 0 }

The following is the content of the students table after execution

MySQL Table students Content

mysql> select　*　from students;　
Empty set (0.00 sec)

Conclusion:

In this Node.js tutorial – Node.js MySQL – DELETE FROM, we learned how to delete records based on conditions or delete all records from the table.