IshaSQL
Interview Core Track · Easy · 15 min
Customers Who Never Order
Table: Customers +-------------+---------+ | Column Name | Type | +-------------+---------+ | id | int | | name | varchar | +-------------+---------+ id is t...
Company labels are directional practice context, not official interview guidance.
Objective
Practice joins through a IshaSQL-tagged business scenario.
Approach
Use this track to improve speed, edge-case handling, and accuracy under timed conditions.
Company context
Company labels are directional practice context, not official interview guidance.
Table: Customers +-------------+---------+ | Column Name | Type | +-------------+---------+ | id | int | | name | varchar | +-------------+---------+ id is the primary key (column with unique values) for this table. Each row of this table indicates the ID and name of a customer. Table: Orders +-------------+------+ | Column Name | Type | +-------------+------+ | id | int | | customerId | int | +-------------+------+ id is the primary key (column with unique values) for this table. customerId is a foreign key (reference columns) of the ID from the Customers table. Each row of this table indicates the ID of an order and the ID of the customer who ordered it. Write a solution to find all customers who never order anything. Return the result table in any order . The result format is in the following example. Example 1: Input: Customers table: +----+-------+ | id | name | +----+-------+ | 1 | Joe | | 2 | Henry | | 3 | Sam | | 4 | Max | +----+-------+ Orders table: +----+------------+ | id | customerId | +----+------------+ | 1 | 3 | | 2 | 1 | +----+------------+ Output: +-----------+ | Customers | +-----------+ | Henry | | Max | +-----------+
Customers
Orders
SQL workspace
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