Hacker News Reader

> Varchars take up the space for all the chars defined.

This only applies to memory tables. For non-memory tables, the size of varchar columns depends on the actual string size.

(edited. Thanks for correcting!)

"MEMORY tables use a fixed-length row-storage format. Variable-length types such as VARCHAR are stored using a fixed length."

I had no idea about this either....

> MEMORY tables use a fixed-length row-storage format. Variable-length types such as VARCHAR are stored using a fixed length.