MySQL - REGEXP_SUBSTR() 函数

要通过 Node.js 程序从 MySQL 数据库中检索与特定模式匹配的字符串部分，我们需要使用 mysql2 库的 query() 函数执行"SELECT"语句，如下所示 -

sql = "SELECT REGEXP_SUBSTR('Welcome To Tutorialspoint!', 'We') AS RESULT";
con.query(sql);

要通过 Java 程序从 MySQL 数据库中检索与特定模式匹配的字符串部分，我们需要使用 JDBC 函数 executeUpdate() 执行"SELECT"语句，如下所示 -

String sql = "SELECT REGEXP_SUBSTR('Welcome To Tutorialspoint!', 'We') AS RESULT";
statement.executeQuery(sql);

要通过 Python 程序从 MySQL 数据库中检索与特定模式匹配的字符串部分，我们需要使用 MySQL Connector/Python 的 execute() 函数执行"SELECT"语句，如下所示 -

sql = "SELECT REGEXP_SUBSTR('Welcome To Tutorialspoint!', 'We') AS RESULT"
cursorObj.execute(sql)

var mysql = require('mysql2');
var con = mysql.createConnection({
host:"localhost",
user:"root",
password:"password"
});
 //连接到 MySQL
 con.connect(function(err) {
 if (err) throw err;
  //console.log("Connected successfully...!");
  //console.log("--------------------------");
 sql = "USE TUTORIALS";
 con.query(sql);
 sql = "SELECT REGEXP_SUBSTR('Welcome To Tutorialspoint!', 'We') AS RESULT";
 console.log("Select query executed successfully..!");
 console.log("Table records: ");
 con.query(sql);
 con.query(sql, function(err, result){
 if (err) throw err;
 console.log(result);
 });
});    

输出

获得的输出如下所示 -

Select query executed successfully..!
Table records:
[ { RESULT: 'We' } ]    

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
public class regexp_substr {
    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 REGEXP_SUBSTR('Welcome To Tutorialspoint!', 'We') AS RESULT";
            rs = st.executeQuery(sql);
            while(rs.next()) {
                String result = rs.getString("RESULT");
                System.out.println("Result: " + result);
            }
        }catch(Exception e) {
            e.printStackTrace();
        }
    }
}    

输出

获得的输出如下所示 -

Result: We

import mysql.connector
# 建立连接
connection = mysql.connector.connect(
    host='localhost',
    user='root',
    password='password',
    database='tut'
)
# 创建游标对象
cursorObj = connection.cursor()
regexp_substr_query = f"SELECT REGEXP_SUBSTR('Welcome To Tutorialspoint!', 'We') AS RESULT"
cursorObj.execute(regexp_substr_query)
# 获取所有结果
results = cursorObj.fetchall()
# 显示结果
print("Result of REGEXP_SUBSTR() Function:")
for row in results:
    result = row[0]
    print(f"The extracted substring is: '{result}'")
cursorObj.close()
connection.close()       

输出

获得的输出如下所示 -

Result of REGEXP_SUBSTR() Function:
The extracted substring is: 'We'