| for select jobs | 10 | purpose |
| always | 8 | degree |
| according to the null bitmap | 6 | other |
| field → be → null | 255 |
| field → be not → null | 26 |
| field → not be → null | 16 |
| field → contain → null | 12 |
| field → not allow → null | 4 |
| negative | neutral | positive |
| 0.320 | 0.635 | 0.044 |
| Raw frequency | 313 |
| Normalized frequency | 0.792 |
| Modifier score | 0.776 |
| Perplexity | 90.659 |