Flash cards
Review the key moves
What is the main idea behind Node.js MySQL Limit?
Lesson checks
Practice each idea before moving on
Short Mimo-style checks built from this lesson's code, terms, and sequence.
Which statement best captures the main point of this lesson?
Complete the missing token from the example code.
___ mysql = require('mysql');Put the learning moves in the order that makes the concept easiest to apply.
Limit the Result
You can limit the number of records returned from the query, by using the "LIMIT" statement:
Example
Select the 5 first records in the "customers" table:
let mysql = require('mysql');
let con = mysql.createConnection({
host: "localhost", user: "yourusername",
password: "yourpassword", database: "mydb"
});
con.connect(function(err) {
if (err) throw err;
let sql = "SELECT * FROM customers LIMIT 5 ";
con.query(sql, function (err, result) {
if (err) throw err;
console.log(result);
});
});Save the code above in a file called "demo_db_limit.js" and run the file:
Run "demo_db_limit.js"
C:\Users\
Your Name
>node demo_db_limit.jsWhich will give you this result
[ { id: 1, name: 'John', address: 'Highway 71'}, { id: 2, name: 'Peter', address: 'Lowstreet 4'}, { id: 3, name: 'Amy', address: 'Apple st 652'}, { id: 4, name: 'Hannah', address: 'Mountain 21'}, { id: 5, name: 'Michael', address: 'Valley 345'}
]Start From Another Position
If you want to return five records, starting from the third record, you can use the "OFFSET" keyword:
Example
Start from position 3, and return the next 5 records:
let mysql = require('mysql');
let con = mysql.createConnection({
host: "localhost", user: "yourusername",
password: "yourpassword", database: "mydb"
});
con.connect(function(err) {
if (err) throw err;
let sql = "SELECT * FROM customers LIMIT 5 OFFSET 2 ";
con.query(sql, function (err, result) {
if (err) throw err;
console.log(result);
});
});Note
"OFFSET 2", means starting from the third position, not the second!
Save the code above in a file called "demo_db_offset.js" and run the file:
Run "demo_db_offset.js"
C:\Users\
Your Name
>node demo_db_offset.jsWhich will give you this result
[ { id: 3, name: 'Amy', address: 'Apple st 652'}, { id: 4, name: 'Hannah', address: 'Mountain 21'}, { id: 5, name: 'Michael', address: 'Valley 345'},
{ id: 6, name: 'Sandy', address: 'Ocean blvd 2'}, { id: 7, name: 'Betty', address: 'Green Grass 1'}
]Shorter Syntax
You can also write your SQL statement like this "LIMIT 2, 5" which returns the same as the offset example above:
Example
Start from position 3, and return the next 5 records:
let mysql = require('mysql');
let con = mysql.createConnection({
host: "localhost", user: "yourusername",
password: "yourpassword", database: "mydb"
});
con.connect(function(err) {
if (err) throw err;
let sql = "SELECT * FROM customers LIMIT 2, 5 ";
con.query(sql, function (err, result) {
if (err) throw err;
console.log(result);
});
});Note
The numbers are reversed: "LIMIT 2, 5" is the same as "LIMIT 5 OFFSET 2"