PostgreSQL:使用join + outer-join +sub select来比较值的问题。

Question

我正在使用postresql，但我真的不擅长构造sql查询。我有一个查询，它可以工作：

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 )

但我也想从底部限制最后一个“拥有”，所以它将是这样的，但它当然不起作用。

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”save之后的值，这样我也可以从底部比较它？谢谢你们所有人。

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，后者在PostgreSQL中通常更快。

。。更易读

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);

您可以对某些列进行表限定化，如pokerhands.site_id，但不对其他列进行限定，如handhistories，您可能需要清理这些列。

Answer 2

间歇期会对你有帮助吗？

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，重用AND关键字)

更新:还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 )