如何加入来自多个SQL查询的结果

Question

我想显示在SELECT中定义的所需列，一旦执行了一个条件并打印条件的结果，我想从SELECT中的新指定列中显示另一个条件条款等等，首先不知何故，我需要解决这两个查询，之后，该计划是混合约10个queires。感谢诗的是，i_di1.naziv

SELECT bolnickiracun.id, 
     bolnickiracun.id_dijagnoza1, i_di1.naziv naziv_dijagnoza1 
FROM  bolnickiracun 
LEFT JOIN i_dijagnoze_marko i_di1 ON bolnickiracun.id_dijagnoza1=i_di1.id 
WHERE bolnickiracun.id_dijagnoza1!="" and i_di1.naziv is null 
UNION ALL 
SELECT bolnickiracun.id, 
     bolnickiracun.id_dijagnoza2, i_di2.naziv naziv_dijagnoza2 
FROM  bolnickiracun 
LEFT JOIN i_dijagnoze_marko i_di2 ON bolnickiracun.id_dijagnoza2=i_di2.id 
WHERE bolnickiracun.id_dijagnoza2!="" and i_di2.naziv is null 

我想结果是这样的结果，一切都显示在列的问题之一：

id id_dijagnoza1 naziv_dijagnoza1 id_dijagnoza2 naziv_dijagnoza2 
1  some data   null    
2  some data   null 
3          some data   null 
4          some data   null 

点是要找到naziv_dijagnoza1或naziv_dijagnoza2哪里是空即，外键显示不存在主键，或者某人导入不存在作为主键的错误外键。

Answer 1

这个例子对于3 SELECT（第三个通过基于可以看到的模式的推论预测）应该有助于理解对于整个查询需要做什么10 SELECT's。您需要在每个SELECT之后的每个列中填写NULL的SELECT子句。

SELECT bolnickiracun.id, bolnickiracun.id_dijagnoza1, i_di1.naziv naziv_dijagnoza1, NULL, NULL, NULL, NULL -- and so on 
FROM  bolnickiracun 
LEFT JOIN i_dijagnoze_marko i_di1 ON bolnickiracun.id_dijagnoza1=i_di1.id 
WHERE bolnickiracun.id_dijagnoza1!="" and i_di1.naziv is null 

UNION ALL 

SELECT bolnickiracun.id, NULL, NULL, bolnickiracun.id_dijagnoza2, i_di2.naziv naziv_dijagnoza2, NULL, NULL -- and so on 
FROM  bolnickiracun 
LEFT JOIN i_dijagnoze_marko i_di2 ON bolnickiracun.id_dijagnoza2=i_di2.id 
WHERE bolnickiracun.id_dijagnoza2!="" and i_di2.naziv is null 

UNION ALL 

SELECT bolnickiracun.id, NULL, NULL, NULL, NULL, bolnickiracun.id_dijagnoza3, i_di3.naziv naziv_dijagnoza3 -- and so on 
FROM  bolnickiracun 
LEFT JOIN i_dijagnoze_marko i_di3 ON bolnickiracun.id_dijagnoza3=i_di3.id 
WHERE bolnickiracun.id_dijagnoza3!="" and i_di3.naziv is null 

列的每SELECT数应是相同的，因为你可以看到，对于3 SELECTš它的7列（每2表接合×3个SELECT S + 1与ID第一列）。对于每个SELECT条款中的每个012条中的21列（1代表id，2代表每个表中，其余的填充NULL s）。 不是漂亮的解决方案，但可能只有像这样的数据库结构。

所以对于10 SELECT的弗里斯特最后应该是这样的：

SELECT bolnickiracun.id, bolnickiracun.id_dijagnoza1, i_di1.naziv naziv_dijagnoza1, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL 
FROM  bolnickiracun 
LEFT JOIN i_dijagnoze_marko i_di1 ON bolnickiracun.id_dijagnoza1=i_di1.id 
WHERE bolnickiracun.id_dijagnoza1!="" and i_di1.naziv is null 

UNION ALL 
... 
UNION ALL 

SELECT bolnickiracun.id, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, bolnickiracun.id_dijagnoza10, i_di10.naziv naziv_dijagnoza10 
FROM  bolnickiracun 
LEFT JOIN i_dijagnoze_marko i_di10 ON bolnickiracun.id_dijagnoza10=i_di10.id 
WHERE bolnickiracun.id_dijagnoza10!="" and i_di10.naziv is null