Easy · Database

Customers Without Orders

Given Customer(id, name) and Orders(id, customerId), return the Customer name for every customer with no order. Keep distinct customer rows even if names repeat; row order does not matter.

Examples

Example 1

{
  "customers": [
    {"id": 1, "name": "Ada"},
    {"id": 2, "name": "Ben"},
    {"id": 3, "name": "Cy"}
  ],
  "orders": [
    {"id": 10, "customerId": 1}
  ]
}

Output: [{"Customer":"Ben"},{"Customer":"Cy"}]

Example 2

{
  "customers": [
    {"id": 4, "name": "Dee"},
    {"id": 5, "name": "Eve"}
  ],
  "orders": [
    {"id": 11, "customerId": 4},
    {"id": 12, "customerId": 5}
  ]
}

Output: []

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