Concerning Clickhouse, yes it does - exactly the same thing e.g. as when you have 2 compressed files containing each 100 sorted rows, when you merge those 200 r

Concerning Clickhouse, yes it does - exactly the same thing e.g. as when you have 2 compressed files containing each 100 sorted rows, when you merge those 200 rows into a single file, sort them and compress them, the result will be smaller than the sum of the 2 separate files. How much you save is again exactly the same as when dealing directly with files: it depends on the data and on the compression algo.