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Node.js - PostgreSQL - select first N rows

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Created by:
Rian-Whitehouse
379

In this article, we would like to show you how to select the first N rows in the PostgreSQL database usingΒ Node.js.

Node.js - PostgreSQL - select first N rows
Data used in the example - HeidiSQL

Note:Β at the end of this article you can find database preparation SQL queries.

const { Client } = require('pg');

const client = new Client({
    host: '127.0.0.1',
    user: 'postgres',
    database: 'database_name',
    password: 'password',
    port: 5432,
});

const fetchUsers = async (count) => {
    try {
        await client.connect(); // gets connection
        const { rows } = await client.query('SELECT * FROM "users" LIMIT $1', [count]);
        console.table(rows);
    } catch (error) {
        console.error(error.stack);
    } finally {
        await client.end();     // closes connection
    }
};

fetchUsers(3); // fetch first 3 rows

Result:Β 

β”Œβ”€β”€β”€β”€β”€β”€β”€β”€β”€β”¬β”€β”€β”€β”€β”¬β”€β”€β”€β”€β”€β”€β”€β”€β”€β”¬β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”¬β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”
β”‚ (index) β”‚ id β”‚  name   β”‚       email       β”‚ country  β”‚
β”œβ”€β”€β”€β”€β”€β”€β”€β”€β”€β”Όβ”€β”€β”€β”€β”Όβ”€β”€β”€β”€β”€β”€β”€β”€β”€β”Όβ”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”Όβ”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€
β”‚    0    β”‚ 1  β”‚  'Tom'  β”‚  'tom@email.com'  β”‚ 'Poland' β”‚
β”‚    1    β”‚ 2  β”‚ 'Chris' β”‚ 'chris@email.com' β”‚ 'Spain'  β”‚
β”‚    2    β”‚ 3  β”‚ 'Jack'  β”‚ 'jack@email.com'  β”‚ 'Spain'  β”‚
β””β”€β”€β”€β”€β”€β”€β”€β”€β”€β”΄β”€β”€β”€β”€β”΄β”€β”€β”€β”€β”€β”€β”€β”€β”€β”΄β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”΄β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”˜

Database preparation

create_tables.sqlΒ file:

CREATE TABLE "users" (
	"id" SERIAL,
	"name" VARCHAR(100) NOT NULL,
	"email" VARCHAR(100) NOT NULL,
	"country" VARCHAR(15) NOT NULL,
	PRIMARY KEY ("id")
);

insert_data.sqlΒ file:

INSERT INTO "users"
    ("name", "email", "country")
VALUES
    ('Tom', 'tom@email.com', 'Poland'),
    ('Chris', 'chris@email.com', 'Spain'),
    ('Jack', 'jack@email.com', 'Spain'),
    ('Kim', 'kim@email.com', 'Vietnam'),
    ('Marco', 'marco@email.com', 'Italy'),
    ('Kate', 'kate@email.com', 'Spain'),
    ('Nam', 'nam@email.com', 'Vietnam');

Native SQL query (used in the above example):

SELECT * 
FROM "users" 
LIMIT 3      -- LIMIT N

Node.js - PostgreSQL - Problems

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