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MySQL : UNION is not getting executed when executed as a view

In lại Tác giả: Walker 123 更新时间:2023-11-29 01:05:38 25 4
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我正在尝试为我创建的 2 个选择语句的 UNION 创建一个 View 。

UNION 在单独执行时工作正常

但问题是当我将它作为 View 执行时,只有 UNION 的第一部分被执行。

我正在使用的查询如下

SELECT DISTINCT products.pid AS id, 
products.pname AS name,
products.p_desc AS description,
products.p_uid AS userid,
products.p_loc AS location,
products.isaproduct AS whatisit
FROM products
UNION

SELECT DISTINCT services.s_id AS id,
services.s_name AS name,
services.s_desc AS description,
services.s_uid AS userid,
services.s_location AS location,
services.isaservice AS whatisit
FROM services
WHERE services.s_name

当我单独执行时,上面的工作正常。但是当我将它用作 View 时,它并没有给我服务部分的结果。

有人可以帮我解决这个问题吗?

câu trả lời hay nhất

如果您可以为上面的每个单独查询提供结果集,然后还为 UNION 查询提供结果集,我们可能会为您的问题提供更好的答案。我的直觉 react 是第二个查询可能会返回重复值,并且由于您使用的是 UNION,因此将删除重复值。如果您使用 UNION ALL,那么将返回所有重复的行。例如,如果第一个查询返回行:

1 name1 description1 10 Home Y
2 name2 description2 20 Work Y

第二行返回:

1 name1 description1 10 Home Y

结果输出将是:

1 name1 description1 10 Home Y
2 name2 description2 20 Work Y

如果您想要返回所有行:

1 name1 description1 10 Home Y
2 name2 description2 20 Work Y
1 name1 description1 10 Home Y

那么您将使用 UNION ALL 而不是 UNION 语句。

关于MySQL : UNION is not getting executed when executed as a view,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/518839/

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Walker 123
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