Consider a DynamoDB table 'Orders' with partition key 'OrderId'. What will the following query return?

Consider a DynamoDB table 'Orders' with partition key 'OrderId'. What will the following query return?

const params = {
  TableName: 'Orders',
  KeyConditionExpression: 'OrderId = :oid',
  ExpressionAttributeValues: { ':oid': { S: 'A123' } }
};
const data = await client.query(params);
console.log(data.Items);