Here is the performance stats of the solution by leszek_g for TSQL Challenge20.
| Attempt | Start Time | Reads | Writes | CPU | Duration (Sec) |
| 1 | Apr 21 2010 11:24PM | 4996 | 10 | 62 | 0.0720 |
| 2 | Apr 21 2010 11:54PM | 4986 | 0 | 78 | 0.0810 |
| 3 | Apr 22 2010 12:24AM | 4986 | 0 | 78 | 0.1490 |
| 4 | Apr 22 2010 12:54AM | 4986 | 0 | 94 | 0.1320 |
| 5 | Apr 22 2010 1:24AM | 4986 | 0 | 78 | 0.0740 |