MySQL UNION ALL与LEFT JOIN返回双精度值

问题描述

我有多个表试图在MySql中使用UNION ALL和LEFT JOIN从所有表中获取值，我使用的查询看起来像下面这样。

(SELECT 
   t1.name,t2.cat,t3.utt,t4.gcost,t4.net
 FROM table_one as t1
   LEFT JOIN table_three as t2
     ON t2.id = t1.ct
   LEFT JOIN table_four as t3
     ON t3.id = t1.ut
   LEFT JOIN table_five as t4
     ON t4.gid = t1.id
 ) UNION ALL
 (SELECT 
   t1.name,t4.net
 FROM table_tow as t1
   LEFT JOIN table_three as t2
     ON t2.id = t1.ct
   LEFT JOIN table_four as t3
     ON t3.id = t1.ut
   LEFT JOIN table_five as t4
     ON t4.gid = t1.id
 )

但上述查询在MySQL中返回双精度值

这是小提琴链接：http://sqlfiddle.com/#!9/bd30ba/1

任何帮助将不胜感激。

谢谢

更新

根据P.Salmon问题了解上述查询用于固定资产应用的完整逻辑，因此固定资产具有多个项目值，例如：

1. 实际价格。
2. 累计折旧
3. 当前值
4. ...

因此，查询中的查询有2个不同的价格/金额，查询应为每个参考行ID返回两个值。

解决方法

谢谢大家的帮助，但这些都没有帮助我，我知道table_five中有重复的ID，来自table_one和table_tow ...解决问题的唯一方法是在table_one，table_tow中添加新的序列ID ... AS

seq_.time();

在插入过程中在table_five中添加相同的顺序..之后，我将查询更改为。

(SELECT 
   t1.name,t2.cat,t3.utt,t4.gcost,t4.net
 FROM table_one as t1
   LEFT JOIN table_three as t2
     ON t2.id = t1.ct
   LEFT JOIN table_four as t3
     ON t3.id = t1.ut
   LEFT JOIN table_five as t4
     ON t4.gid = t1.id
     AND t4.seq = t1.seq
 ) UNION ALL
 (SELECT 
   t1.name,t4.net
 FROM table_tow as t1
   LEFT JOIN table_three as t2
     ON t2.id = t1.ct
   LEFT JOIN table_four as t3
     ON t3.id = t1.ut
   LEFT JOIN table_five as t4
     ON t4.gid = t1.id
    AND t4.seq = t1.seq
 )

现在我可以根据需要获取确切的数据。 谢谢

,

您只想要一个，而实际上并不在乎哪个，然后最大化t5的详细信息

select t1.name,t3.cat,t4.utt,t5.gcost,t5.net
 from
 (
 select * from table_one
 union all
 select * from table_two) t1
 LEFT JOIN table_three as t3 ON t3.id = t1.ct
 LEFT JOIN table_four as t4            ON t4.id = t1.ct
 left join (select gid,max(gcost) gcost,max(net) net from table_five group by gid) t5 on t5.gid = t1.id;
+--------------+------+------+-------+------+
| name         | cat  | utt  | gcost | net  |
+--------------+------+------+-------+------+
| Green Apple  | A    | AAA  |  3000 | 6542 |
| Small Orange | B    | BBB  |  2560 | 6542 |
| Small Banana | C    | CCC  |  5800 | 6542 |
| Small Mango  | C    | DDD  |  2560 | 6542 |
| Red Apple    | A    | AAA  |  3000 | 6542 |
| Big Orange   | B    | BBB  |  2560 | 6542 |
| Big Banana   | C    | CCC  |  5800 | 6542 |
| Big Mango    | C    | DDD  |  2560 | 6542 |
+--------------+------+------+-------+------+
8 rows in set (0.072 sec)