MySQL - 不等于运算符

要通过 Node.js 程序对 MySQL 表执行 NOT EQUAL 运算符，我们需要使用mysql2 库的query() 函数执行带有 NOT EQUAL 运算符的 SELECT 语句，如下所示：

sql= "SELECT column1, column2, ... FROM table_name 
WHERE column_name <> value";
con.query(sql);

要通过 Java 程序对 MySQL 表执行 NOT EQUAL 运算符，我们需要使用JDBC 函数executeUpdate() 执行带有 NOT EQUAL 运算符的 SELECT 语句，如下所示：

String sql = "SELECT column1, column2, ... FROM table_name 
WHERE column_name <> value";
statement.executeQuery(sql);

要通过 Python 程序对 MySQL 表执行 NOT EQUAL 运算符，我们需要使用 MySQLConnector/Python 的execute() 函数执行带有 NOT EQUAL 运算符的 SELECT 语句，如下所示：

not_equal_query = "SELECT column1, column2, ... FROM table_name 
WHERE column_name <> value"
cursorObj.execute(not_equal_query);

var mysql = require('mysql2');
var con = mysql.createConnection({
    host: "localhost",
    user: "root",
    password: "Nr5a0204@123"
});

  //Connecting to MySQL
  con.connect(function (err) {
  if (err) throw err;
  console.log("Connected!");
  console.log("--------------------------");

  //Creating a Database
  sql = "create database TUTORIALS"
  con.query(sql);

  //Select database
  sql = "USE TUTORIALS"
  con.query(sql);

  //Creating CUSTOMERS table
  sql = "CREATE TABLE CUSTOMERS (ID INT NOT NULL, NAME VARCHAR(20) NOT NULL, AGE INT NOT NULL, ADDRESS CHAR(25), SALARY DECIMAL(18, 2), PRIMARY KEY(ID));"
  con.query(sql);

  //Inserting Records
  sql = "INSERT INTO CUSTOMERS(ID, NAME, AGE, ADDRESS, SALARY) VALUES(1,'Ramesh', 32, 'Hyderabad',4000.00),(2,'Khilan', 25, 'Kerala', 8000.00),(3,'kaushik', 23, 'Hyderabad', 11000.00),(4,'Chaital', 25, 'Mumbai', 1200.00),(5,'Hardik', 27, 'Vishakapatnam', 10000.00),(6, 'Komal',29, 'Vishakapatnam', 7000.00),(7, 'Muffy',24, 'Delhi', 10000.00);"
  con.query(sql);

  //Using NOT EQUAL Operator
  sql = "SELECT * FROM CUSTOMERS WHERE NAME <> 'Muffy';"
  con.query(sql, function(err, result){
    if (err) throw err
    console.log(result)
  });
});  

输出

生成的输出如下：

Connected!
--------------------------
[
  {
    ID: 1,
    NAME: 'Ramesh',
    AGE: 32,
    ADDRESS: 'Hyderabad',
    SALARY: '4000.00'
  },
  {
    ID: 2,
    NAME: 'Khilan',
    AGE: 25,
    ADDRESS: 'Kerala',
    SALARY: '8000.00'
  },
  {
    ID: 3,
    NAME: 'kaushik',
    AGE: 23,
    ADDRESS: 'Hyderabad',
    SALARY: '11000.00'
  },
  {
    ID: 4,
    NAME: 'Chaital',
    AGE: 25,
    ADDRESS: 'Mumbai',
    SALARY: '1200.00'
  },
  {
    ID: 5,
    NAME: 'Hardik',
    AGE: 27,
    ADDRESS: 'Vishakapatnam',
    SALARY: '10000.00'
  },
  {
    ID: 6,
    NAME: 'Komal',
    AGE: 29,
    ADDRESS: 'Vishakapatnam',
    SALARY: '7000.00'
  }
]         

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
public class NotEqualOperator {
  public static void main(String[] args) {
    String url = "jdbc:mysql://localhost:3306/TUTORIALS";
    String user = "root";
    String password = "password";
    ResultSet rs;
    try {
      Class.forName("com.mysql.cj.jdbc.Driver");
            Connection con = DriverManager.getConnection(url, user, password);
            Statement st = con.createStatement();
            //System.out.println("Database connected successfully...!");
            String sql = "SELECT * FROM CUSTOMERS WHERE NAME <> 'Muffy'";
            rs = st.executeQuery(sql);
            System.out.println("Table records: ");
            while(rs.next()) {
              String id = rs.getString("Id");
              String name = rs.getString("Name");
              String age = rs.getString("Age");
              String address = rs.getString("Address");
              String salary = rs.getString("Salary");
              System.out.println("Id: " + id + ", Name: " + name + ", Age: " + age + ", Addresss: " + address + ", Salary: " + salary);
            }
    }catch(Exception e) {
      e.printStackTrace();
    }
  }
}                                  

输出

获得的输出如下所示：

Table records: 
Id: 1, Name: Ramesh, Age: 32, Addresss: Ahmedabad, Salary: 2000.00
Id: 2, Name: Khilan, Age: 30, Addresss: Delhi, Salary: 1500.00
Id: 3, Name: kaushik, Age: 23, Addresss: Kota, Salary: 2000.00
Id: 4, Name: Chaitali, Age: 30, Addresss: Mumbai, Salary: 6500.00
Id: 5, Name: Hardik, Age: 30, Addresss: Bhopal, Salary: 8500.00
Id: 6, Name: Komal, Age: 22, Addresss: MP, Salary: 4500.00              

import mysql.connector
#establishing the connection
connection = mysql.connector.connect(
    host='localhost',
    user='root',
    password='password',
    database='tut'
)
cursorObj = connection.cursor()
not_equal_query = f"""
SELECT * FROM CUSTOMERS WHERE NAME <> 'Muffy';
"""
cursorObj.execute(not_equal_query)
# Fetching all the rows that meet the criteria
filtered_rows = cursorObj.fetchall()
for row in filtered_rows:
    print(row)
cursorObj.close()
connection.close()                               

输出

以上代码的输出如下：

(1, 'Ramesh', 32, 'Hyderabad', Decimal('4000.00'))
(2, 'Khilan', 25, 'Kerala', Decimal('8000.00'))
(3, 'kaushik', 23, 'Hyderabad', Decimal('11000.00'))
(4, 'Chaital', 25, 'Mumbai', Decimal('1200.00'))
(5, 'Hardik', 27, 'Vishakapatnam', Decimal('10000.00'))
(6, 'Komal', 29, 'Vishakapatnam', Decimal('7000.00'))