SQL-UNION，在执行以下命令时优先于第一个选择语句

Question

我试图首先从“ GermanDB”数据库中打印出结果，同时还显示来自Boston DB的所有德语数据库中未包含的内容。 可以在一个查询中完成吗？

我的查询（粗体部分起作用，但未按我想要的方式排序）

select * from (  
SELECT DISTINCT a.ProductRef  
FROM GERMANDB.dbo.LOCATIONS AS a INNER JOIN GERMANDB.dbo.ITEMS AS b ON a.ProductRef =   b.ProductRef   
WHERE b.ACTIVE=1  
) ta  
UNION select * from  
SELECT DISTINCT c.ProductRef  
FROM BOSTONDB.dbo.LOCATIONS AS c INNER JOIN BOSTONDB.dbo.ITEMS AS d ON c.ProductRef =   d.ProductRef   
WHERE c.ACTIVE=1 (c.ProductRef NOT IN   
(SELECT ProductRef FROM GERMANDB.dbo.ITEMS where ACTIVE=1))  
) tb  
order by ta.ProductRef** , tb.productRef

Answer 1

只需添加一个字段即可发出优先级信号。 像这样：

select *, 0 as Priority from (  
SELECT DISTINCT a.ProductRef  
FROM GERMANDB.dbo.LOCATIONS AS a INNER JOIN GERMANDB.dbo.ITEMS AS b ON a.ProductRef =   b.ProductRef   
WHERE b.ACTIVE=1  
) ta  
UNION select *, 1 as Priority from  
SELECT DISTINCT c.ProductRef  
FROM BOSTONDB.dbo.LOCATIONS AS c INNER JOIN BOSTONDB.dbo.ITEMS AS d ON c.ProductRef =   d.ProductRef   
WHERE c.ACTIVE=1 (c.ProductRef NOT IN   
(SELECT ProductRef FROM GERMANDB.dbo.ITEMS where ACTIVE=1))  
) tb  
order by Priority, ProductRef