A Way to Do Group By

Mon, 10 Jun 2019 13:00:00 +0000

How do you do Group By in SQL ? (or MySql) ? This post is note about my experience writing query in sql, There is worth-to-note something about ‘Group By’, there is may be better way to do it.

So lets say, we have following schema, table users and table orders, they have relation one to many. One user can has zero or many orders.

 1CREATE TABLE orders
 2(
 3 id INT(11) PRIMARY KEY NOT NULL AUTO_INCREMENT,
 4 title VARCHAR(500) NOT NULL,
 5 order_date DATE NOT NULL,
 6 user_id INT(11) NOT NULL
 7);
 8
 9CREATE TABLE users
10(
11 id INT(10) unsigned PRIMARY KEY NOT NULL AUTO_INCREMENT,
12 name VARCHAR(255) NOT NULL,
13 email VARCHAR(255) NOT NULL,
14);
15
16CREATE UNIQUE INDEX users_email_unique ON users (email);

and suppose we need to get all users for certain order, for SELECT * fan, the query pretty much will looks like this

Sql on egig.github.io

A Way to Do Group By