可以合并和合并线吗? [英] Can union and combined line ?

问题描述

我有个例子:

I have example:

SELECT 1 AS ID, 'a' AS NAME1, null AS NAME2
UNION
SELECT 1 AS ID, 'a' AS NAME1, 'b' AS NAME2

结果:

ID NAME1 NAME2
1个为空
1 a b

如何结合?

ID NAME1 NAME2
1 a b

Result:

ID NAME1 NAME2
1 a null
1 a b

How can it combined ?

ID NAME1 NAME2
1 a b

推荐答案

您不能.您进行了一个联合，要求输入null值，所以有了它.我不知道合并"是什么意思，但是在两种情况下您都选择了与NAME1相同的内容，因此没有什么可以合并的.您可以得到所要的东西，并且根据您的问题，除了删除工会以外，您什么都不需要.

you can''t. You did a union asking for the null value, so you have it. I don''t know what you mean by ''combined'', but you are selecting the same thing as NAME1 in both cases, so there''s nothing to combine. You''re getting exactly what you asked for, and based on your question, there''s nothing else you could want, apart from removing the union

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