I tried to do a fair job in recreating your queries and techniques with MSSQL. Turns out MSSQL picks the best plan from the start [1]. [1] https://news.ycombin

I tried to do a fair job in recreating your queries and techniques with MSSQL. Turns out MSSQL picks the best plan from the start [1]. [1] https://news.ycombinator.com/item?id=7119976 https://news.ycombinator.com/item?id=7119976 or http://ta.speot.is/2014/01/25/use-subqueries-to-count-distinct-0x-faster/ http://ta.speot.is/2014/01/25/use-subqueries-to-count-distin...