Re: Sorting of data before query improves efficiency?

[Peter Brawley]

> the whole block gets appended below the table.

New rows are added wherever the engine wants to put them. A fundamental rule of relational databases, the ISO standard, is that physical row order has no effects, so queries without Order By clauses return results in unpredictable order.

Against that ISO standard, MySQL implements Alter Table ...Order By..., but its effects are undone by the next PK update, insert or delete, ie it's useless in tables where data may change and is not reliable even in static tables.

Use Order By clauses in your queries to order row display.