| Question; Answer; Project | |
| What is the aggregate function singleValueOrNull used to implement?; subquery operators; ClickHouse | |
| What checks if there is only one unique non-NULL value in the data?; singleValueOrNull; ClickHouse | |
| If there are zero or at least two distinct values, what does singleValueOrNull return?; NULL; ClickHouse | |
| What is the unique value if there is only one unique non-NULL value in x?; NULL; ClickHouse | |
| What does ASF stand for?; Apache Software Foundation; Druid | |
| What does the ASF license this file to you under?; Apache License, Version 2.0; Druid | |
| What is the primary goal of the integration setup?; the ability to quickly debug the Druid image and any individual tests; Druid | |
| What is the second step of the integration setup?; ensure each test can run in JUnit in an IDE against a cluster you start by hand; Druid | |
| What is a key goal of the revised structure?; Ease of debugging; Druid | |