Question

我有这个查询，效果很好。我使用MIN(home_price)显示为起始价格，我使用此查询来添加api和WHERE子句，因此如果我按价格搜索MIN(home_price)更改。

SELECT MIN(home_price) as min_home_price,
   id,
   name,
   community,
   maplocation,
   locationLabel,
   logo 
FROM ourCommunity 
INNER JOIN readyBuilt 
   ON community = home_community 
INNER JOIN rb_locations 
   ON readyBuilt.home_location = rb_locations.locationId 
WHERE id IN ( SELECT DISTINCT id 
                 FROM ourCommunity 
                 INNER JOIN readyBuilt 
                        ON community = home_community 
                 WHERE isDeleted = 0 AND is_upcoming = 0) 
   AND home_status = 1 
 GROUP BY id,name,community,mapLocation,locationLabel,logo 
 ORDER BY name

所以我的解决方案是使用子查询

SELECT id,
   name,
   community,
   maplocation,
   locationLabel,
   logo, 
   (SELECT MIN(home_price) as min_home_price 
          FROM ourCommunity 
          INNER JOIN readyBuilt 
                 ON community = home_community 
          INNER JOIN rb_locations 
                 ON readyBuilt.home_location = rb_locations.locationId 
          WHERE id IN ( SELECT DISTINCT id 
                        FROM ourCommunity 
                        INNER JOIN readyBuilt 
                               ON community = home_community 
                        WHERE isDeleted = 0 
                               AND is_upcoming = 0) 
                 AND home_status = 1 
          GROUP BY id,name,community,mapLocation,locationLabel,logo 
          ORDER BY name) as org_min_home_price 
FROM ourCommunity 
INNER JOIN readyBuilt 
   ON community = home_community 
INNER JOIN rb_locations 
   ON readyBuilt.home_location = rb_locations.locationId 
WHERE id IN ( SELECT DISTINCT id 
                 FROM ourCommunity 
                 INNER JOIN readyBuilt 
                        ON community = home_community 
                 WHERE isDeleted = 0 AND is_upcoming = 0) 
   AND home_status = 1 
 GROUP BY id,name,community,mapLocation,locationLabel,logo 
 ORDER BY name

但是当我执行第二个查询时，我收到此错误

子查询返回超过1行

当我删除GROUP BY时，我发现MIN(home_price)没有错误，每行都是相同的。有没有人对如何完成我想要完成的事情有任何建议？

Answer 1

通常情况下，如果您添加price作为过滤器，则返回的最低价格将不会是该表的实际最小值。

您可以加入由社区

分组的每分钟（home_price）的结果集

SELECT min_home_price,   
   id,
   name,
   community,
   maplocation,
   locationLabel,
   logo 
FROM ourCommunity
INNER JOIN (select min(home_price) min_home_price, home_community from readyBuilt group by home_community) b on b.home_community = community
INNER JOIN readyBuilt a ON community = a.home_community 
INNER JOIN rb_locations ON a.home_location = rb_locations.locationId 
WHERE id IN ( SELECT DISTINCT id 
                 FROM ourCommunity 
                 INNER JOIN readyBuilt ON community = home_community 
                 WHERE isDeleted = 0) 
AND home_status = 1 
GROUP BY id,name,community,mapLocation,locationLabel,logo 
ORDER BY name;

Answer 2

不要在MySQL中使用嵌套子查询来处理大型数据集，否则MySQL最终可能会自行创建临时表，并且查询性能会受到影响。

我尝试删除最后一个嵌套查询，如下所示：

SELECT b.min_home_price,   
oc.id, oc.name, oc.community, oc.maplocation, oc.locationLabel, oc.logo
FROM ourCommunity oc
INNER JOIN (select min(home_price) min_home_price, home_community from readyBuilt group by home_community) b on b.home_community = oc.community
INNER JOIN readyBuilt rb ON oc.community = rb.home_community 
INNER JOIN rb_locations rbl ON rb.home_location = rbl.locationId 
INNER JOIN readyBuilt rb1 ON oc.community = rb1.home_community
WHERE rb1.isDeleted = 0
AND oc.home_status = 1 
 GROUP BY oc.id, oc.name, oc.community, oc.mapLocation, oc.locationLabel, oc.logo 
 ORDER BY oc.name;

如果你能用简单的英语上传你的3个表格定义和整体目标，即WHAT你试图实现而不是从HOW开始你开始解决问题，可能是我可以帮助简化查询。

Answer 3

在你的第二个查询中，当你没有选择小组时，你只会获得一行，因为你正在为整个表选择min（home_price）。

当您添加＆＃34; group by＆＃34;时，您将获得每个ID，每个社区等每个ID的分钟（home_price）。

您需要更改子查询以获取外部查询的当前行的min（home_price）。可以将子查询看作是根据某些参数（恰好与外部查询中的列匹配）返回值的函数。

我还怀疑你在子查询中只需要一个表 - 一个有价格的表。其他表可能会为您提供位置分组，因此它们属于外部查询。（尝试让外部查询在没有最低价格和最后价格的情况下工作。）

E.g

选择ID，名称等... ，（（从p中选择min（price）其中p.id = oc.id ）作为minPrice 来自我们的社区oc 内联等...... 分组......

正如其他答案所示，有很多方法可以实现这一点，例如连接而不是子查询。除非性能是一个问题，否则每个都有利弊，只需使用最容易理解和维护的内容。

MySQL Group不在子查询中工作

3 个答案: