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SQL

Keep four assets distinct

BOTIE

Project asset_id and kind from the register. Compare the repeated kinds with the distinct IDs.
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Live values

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Context for this challenge

Project asset_id and kind from the register. Compare the repeated kinds with the distinct IDs.

Several register entries describe pumps. The result must preserve each asset identity.

Inspect the component calculation
Choose table columns(
  Rows: Asset register
  Columns, separated by commas: asset_id,kind
)
Examples and results
Asset register
[
  {
    "asset_id": "P1",
    "site": "north",
    "kind": "pump"
  },
  {
    "asset_id": "P2",
    "site": "north",
    "kind": "fan"
  },
  {
    "asset_id": "P3",
    "site": "south",
    "kind": "pump"
  },
  {
    "asset_id": "P4",
    "site": "south",
    "kind": "pump"
  }
]
Required result
[
  {
    "asset_id": "P1",
    "kind": "pump"
  },
  {
    "asset_id": "P2",
    "kind": "fan"
  },
  {
    "asset_id": "P3",
    "kind": "pump"
  },
  {
    "asset_id": "P4",
    "kind": "pump"
  }
]
Try a fresh construction

This clears this draft, including its undo history. Earlier successful attempts stay recorded. Build again without opening hints to record an independent attempt.

Stuck? Inspect a worked construction

The tools below form one possible solution. You can assemble it, follow its signals, and undo that change to return to your own construction.

Assumptions and test precision

The workshop calculates over small record lists to make the relational operations visible. It is not a SQL parser or query planner. The worksheet runs SQLite and is the authority for SQL behaviour, including types and NULL. Numerical tests allow a difference of 0.001. Lists and structures must also have the right shape.

Your last tested pieces can start the full construction. An existing draft there keeps its own pieces.

Two identical descriptions still have different identities

This check uses the pieces from “Preserve the asset identity”.

BOTIE

The new register contains P9 and P8, both fans at west. Predict the asset-ID and kind report without collapsing the two real assets.
Asset register
[
  {
    "asset_id": "P9",
    "site": "west",
    "kind": "fan"
  },
  {
    "asset_id": "P8",
    "site": "west",
    "kind": "fan"
  }
]

Use a number, text, or an array matching the requested result. For a matrix, put each row in brackets. Saving your prediction runs your current construction on these inputs and checks the earlier examples too.

Build a construction in the workspace above first. This case will test those pieces.

What would one row mean if we removed asset_id and then kept only distinct kinds?

Name the row grain before selecting, counting or combining records.

The workshop calculates over small record lists to make the relational operations visible. It is not a SQL parser or query planner. The worksheet runs SQLite and is the authority for SQL behaviour, including types and NULL.

Work through the SQL challenges →
Continue the courseWhich Columns Answer the Question? →
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