Question

我想使用UNION从数据库中获取数据，我将链接定义为新闻链接，将图片定义为articlepic，但它在newslink列下显示了文章图片数据，我该如何解决？

SELECT * FROM
((SELECT date, link as newslink FROM news ORDER BY id DESC)
UNION
(SELECT date, pic as articlepic FROM article ORDER BY id DESC)) as x
ORDER BY date DESC LIMIT 6

Sample Data

我想在articlepic列下获取文章数据，并在newslink列下获取新闻链接

Answer 1

如果您在其他列中输入值，则必须在select中为不对应的列添加空值

SELECT * FROM
 ((SELECT date, link as newslink, null as articlepic 
  FROM news ORDER BY id DESC)
UNION
 (SELECT date, null, pic 
   FROM article ORDER BY id DESC)) as x
ORDER BY date DESC LIMIT 6

Answer 2

在查询中使用并集时，您将无法获得列的其他名称

SELECT * FROM
    (
        (
        SELECT
            DATE,
            link AS newslink,
            '-'  As articlepic         
        FROM news ORDER BY id DESC
    ) UNION (
    SELECT
        DATE,
        '-'  As newslink,         
        pic AS articlepic
    FROM article ORDER BY id DESC
)
    ) AS X
ORDER BY DATE DESC LIMIT 6

mysqli UNION以正确的列名获取数据

2 个答案: