Originally posted by abhaysk
[BWhy not...and why do u wana go for dumping all blocks to know which extent has how many rows.. crazy idea.. [/B]
Khm, not so crazy. In fact, as I said, it's the only way to find out if the block contains any data or not (for tables, anyway; indexes are even more complicated).

Neither of your queries will display correct result with 100% accuracy, some blocks that actually contain data might not be encountered by your queries.

Speaking about crazy ideas - the only crazy idea in this thread was the requirement to find which blocks contain any data and which do not. I mean, even if it can be done, what would the result tell you anyway?