HTML tutorial
CSS3 tutorial
Bootstrap tutorial
JavaScript tutorial
JQuery tutorial
AngularJS tutorial
React tutorial
NodeJS tutorial
PHP tutorial
Python tutorial
Python3 tutorial
Django tutorial
Linux tutorial
Docker tutorial
Ruby tutorial
Java tutorial
C tutorial
C ++ tutorial
Perl tutorial
JSP tutorial
Lua tutorial
Scala tutorial
Go tutorial
ASP.NET tutorial
C # tutorial
You can delete records from an existing table by using the "DELETE FROM" statement
You can delete records from an existing table by using the "DELETE FROM" statement:
Delete any record with the address "Mountain 21":
var mysql = require('mysql');
var con = mysql.createConnection({
host: "localhost",
user: "yourusername",
password: "yourpassword",
database: "mydb"
});
con.connect(function(err) {
if (err) throw err;
var sql = "DELETE FROM customers WHERE address = 'Mountain 21'";
con.query(sql, function (err, result) {
if (err) throw err;
console.log("Number of records
deleted: " + result.affectedRows);
});
});
Notice the WHERE clause in the DELETE syntax: The WHERE clause specifies which record or records that should be deleted. If you omit the WHERE clause, all records will be deleted!
Save the code above in a file called "demo_db_delete.js" and run the file:
Run "demo_db_delete.js"
C:\Users\Your Name>node demo_db_delete.js
Which will give you this result:
Number of records deleted: 1
When executing a query, a result object is returned.
The result object contains information about how the query affected the table.
The result object returned from the example above looks like this:
{
fieldCount: 0,
affectedRows: 1,
insertId: 0,
serverStatus: 34,
warningCount: 0,
message: '',
protocol41: true,
changedRows: 0
}
The values of the properties can be displayed like this:
Return the number of affected rows:
console.log(result.affectedRows)
Which will produce this result:
1