PostgreSQL:连接+外连接+子选择比较值的问题

Question

我正在使用postresql，但我在构建sql查询方面真的很糟糕。我有这个查询，它工作:

SELECT handhistories FROM handhistories 
JOIN pokerhands using (pokerhand_id)  
JOIN gametypes using (gametype_id)
RIGHT OUTER JOIN playerhandscashkeycolumns using (pokerhand_id)
     WHERE pokerhands.site_id=0  
     AND pokerhands.numberofplayers>=5 and  pokerhands.numberofplayers<=7
     AND (bigblind = 2 OR bigblind = 4 )
     AND player_id in 
        (SELECT player_id FROM playerhandscashkeycolumns GROUP BY player_id
         HAVING AVG(case didvpip when true then 100::real else 0 end) <= 20 )

但是我还想限制最后一个"having"从底部开始，所以它将是这样的，但当然它不起作用。

SELECT handhistories FROM handhistories 
JOIN pokerhands using (pokerhand_id)  
JOIN gametypes using (gametype_id)
RIGHT OUTER JOIN playerhandscashkeycolumns using (pokerhand_id)
       WHERE pokerhands.site_id=0  
       AND pokerhands.numberofplayers>=5 and  pokerhands.numberofplayers<=7
       AND (bigblind = 2 OR bigblind = 4 )
       AND player_id in 
        (SELECT player_id FROM playerhandscashkeycolumns GROUP BY player_id
         HAVING AVG(case didvpip when true then 100::real else 0 end) <= 20
         AND  HAVING AVG(case didvpip when true then 100::real else 0 end) > 10 )

如何"保存"值之后，所以我可以比较它也从底部?谢谢大家。

Answer 1

这主要是@wildplasser已经指出的
. .减去BETWEEN
的错误. .加上JOIN代替IN结构，这通常在PostgreSQL中更快。
. .更容易阅读

SELECT handhistories
FROM   handhistories
JOIN   pokerhands USING (pokerhand_id)  
JOIN   gametypes USING (gametype_id)
RIGHT  JOIN playerhandscashkeycolumns USING (pokerhand_id)
JOIN   (
    SELECT player_id
    FROM   playerhandscashkeycolumns
    GROUP  BY player_id
    HAVING avg(CASE WHEN didvpip THEN 100::real ELSE 0 END) >  10
    AND    avg(CASE WHEN didvpip THEN 100::real ELSE 0 END) <= 20
    ) p USING (player_id)
WHERE  pokerhands.site_id = 0  
AND    pokerhands.numberofplayers BETWEEN 5 AND 7
AND    bigblind IN (2,4);

您对某些列(如pokerhands.site_id)进行了表限定，但对其他列(如handhistories)不进行了表限定，您可能需要将其清除。

Answer 2

BETWEEN适合你吗?

HAVING AVG(case didvpip when true then 100::real else 0 end) BETWEEN 10 AND 20

(BTW:丑陋的SQL语法，重用AND关键字)

UPDATE:也可以用来简化查询的其余部分:

AND pokerhands.numberofplayers BETWEEN 5 AND 7
AND bigblind IN ( 2, 4 )