NodeJs MySQL TRIM()函数
TRIM()函数是 MySQL 中的一个内置函数,用于修剪输入字符串两侧的所有空格。
句法:
TRIM(string)
参数:它需要一个参数,如下所示:
- 字符串 : 从两边修剪的字符串。
返回值:从两边修剪后返回字符串。
模块安装:使用以下命令安装mysql模块:
npm install mysql
示例 1:硬编码查询
index.js
const mysql = require("mysql");
let db_con = mysql.createConnection({
host: "localhost",
user: "root",
password: '',
database: 'gfg_db'
});
db_con.connect((err) => {
if (err) {
console.log("Database Connection Failed !!!", err);
return;
}
console.log("We are connected to gfg_db database");
// Here is the query
let query =
`SELECT TRIM(' Geeks For Geeks ') AS TRIM_Output`;
db_con.query(query, (err, rows) => {
if(err) throw err;
console.log(rows);
});
});
index.js
const mysql = require("mysql");
let db_con = mysql.createConnection({
host: "localhost",
user: "root",
password: '',
database: 'gfg_db'
});
db_con.connect((err) => {
if (err) {
console.log("Database Connection Failed !!!", err);
return;
}
console.log("We are connected to gfg_db database");
// Notice the ? in query
let query = `SELECT TRIM(?) AS TRIM_Output`;
// Dynamic Input
let input_string = " Pratik Raut ";
// Notice Second Dynamic Parameter
db_con.query(query, input_string, (err, rows) => {
if(err) throw err;
console.log(rows);
});
});
使用以下命令运行index.js文件:
node index.js
输出:
示例 2:动态查询
索引.js
const mysql = require("mysql");
let db_con = mysql.createConnection({
host: "localhost",
user: "root",
password: '',
database: 'gfg_db'
});
db_con.connect((err) => {
if (err) {
console.log("Database Connection Failed !!!", err);
return;
}
console.log("We are connected to gfg_db database");
// Notice the ? in query
let query = `SELECT TRIM(?) AS TRIM_Output`;
// Dynamic Input
let input_string = " Pratik Raut ";
// Notice Second Dynamic Parameter
db_con.query(query, input_string, (err, rows) => {
if(err) throw err;
console.log(rows);
});
});
使用以下命令运行index.js文件:
node index.js
输出: