Node.js MySQL LEFT() Function
Last Updated :
07 Oct, 2021
LEFT() Function is a Builtin function in MySQL which is used to get Prefix of a specific size of Given String.
Syntax:
LEFT(input_string, size_of_prefix)
Parameters: LEFT() function accepts two parameters as mentioned above and described below.
- input_string: We will get prefix of this input string
- size_of_prefix: Number of characters in the prefix
Return Value: LEFT() function returns a string which is a prefix of input_string of specific size.
Modules:
- mysql: To handle MySQL Connection and Queries
npm install mysql
SQL publishers Table Preview:
Example 1: Static Query
Javascript
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" );
let query = "SELECT LEFT(name, 4) AS prefix_name FROM publishers" ;
db_con.query(query, (err, rows) => {
if (err) throw err;
console.log(rows);
});
});
|
Output:
Example 2: Dynamic Query
Javascript
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" );
let query = "SELECT LEFT(salary, ?) AS prefix_salary FROM publishers" ;
let sizeOfPrefix = 3;
db_con.query(query, sizeOfPrefix, (err, rows) => {
if (err) throw err;
console.log(rows);
});
});
|
Output:
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