PostgreSQL：连接问题外连接 +子选择以比较值。

Question

我正在使用 postresql，但我真的不擅长构建 sql 查询。 我有这个查询并且它有效：

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 )

但我也想限制底部的最后一个“having”，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”拥有之后的值，以便我也可以从底部进行比较？ 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 而不是 IN 构造，这在 PostgreSQL 中通常更快。
.. 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);

您对某些列进行了表限定，例如 pokerhands.site_id，但不对其他列进行表限定，例如 handhistories，您可能需要清理它们。

Answer 2

BETWEEN 适合你吗？

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

（顺便说一句：丑陋的 SQL 语法，重复使用 AND 关键字）

更新：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 )