Question

Table 1:Domain Link Result
======================================================================
||Column1(words)     ||Column2(links)    ||Column3(frequency)       ||
======================================================================
    1                   1                   Any Number
    2                   1                   Any Number
    3                   1                   Any Number
    4                   1                   Any Number
    1                   2                   Any Number
    2                   2                   Any Number
    3                   2                   Any Number
    4                   2                   Any Number


Table 2:Sub Link Result
======================================================================
||Column1(words)     ||Column2(sublinks)    ||Column3(frequency)    ||
======================================================================
    1                   a                   Any Number
    2                   b                   Any Number
    3                   c                   Any Number
    4                   d                   Any Number
    1                   e                   Any Number
    2                   f                   Any Number
    3                   g                   Any Number
    4                   h                   Any Number

And so on.

在上面的场景中，用户输入了4个单词和2个域名链接。现在，4个关键字的频率在域链接和子链接上计算，并存储在单独的表中，如上所示。我想要一个如下的汇总结果：

Table 3:Final Result
==================================================================================
||Column1(words)     ||Column2(Domain links)    ||Column3(Total frequency)      ||
==================================================================================
Row1:    1              1                    Total of frequency in both tables
                        2                    for word "1"   
----------------------------------------------------------------------------------
Row2:    2              1                    Total of frequency in both tables
                        2                    for word "2"   
----------------------------------------------------------------------------------
Row3:    3              1                    Total of frequency in both tables
                        2                    for word "3"   
----------------------------------------------------------------------------------
Row4:    4              1                    Total of frequency in both tables
                        2                    for word "4"   
----------------------------------------------------------------------------------

我在MySQL中尝试了以下查询：

SELECT t.`keyword`, t.`link` SUM( t.`frequency` ) AS total
FROM (

SELECT `frequency`
FROM `domain_link_result`
WHERE `keyword` = 'national'
UNION ALL
SELECT `frequency`
FROM `sub_link_result`
WHERE `keyword` = 'national'
)t GROUP BY `keyword`

但是在最终结果的第2列中，我只得到第一个链接而不是第1行的两个链接。如何在一行中获得用户输入的链接或任意数量的链接？

单词和链接的VARCHAR类型和频率为INT类型。

Answer 1

如果您要将多个行折叠为一个仍然能够查看信息，则必须使用GROUP_CONCAT

http://dev.mysql.com/doc/refman/5.0/en/group-by-functions.html#function_group-concat

这将输出以逗号分隔的折叠值，即：一个字符串。在您的编程语言中，如果需要单独的值，可以拆分此字符串。

您的查询看起来会像这样

SELECT keyword, GROUP_CONCAT(links), SUM(frequency)

FROM (subquery)

GROUP BY keyword

哪个会输出这样的东西：

==================================================================================
||Column1(words)     ||Column2(Domain links)    ||Column3(Total frequency)      ||
==================================================================================
Row1:    1              1,2                     sum of freq.
----------------------------------------------------------------------------------
Row2:    2              1,2                     sum of freq.
----------------------------------------------------------------------------------
Row3:    3              1,2                     sum of freq.
----------------------------------------------------------------------------------
Row4:    4              1,2                     sum of freq.

编辑：您的查询的额外帮助

您的查询对我来说有点混乱。尝试使用JOIN方法：

SELECT domain_link_results.word AS word,
       GROUP_CONCAT(domain_link_results.links) AS domain_links,
       domain_link_results.frequency + sub_link_results.frequency AS total_frequency

FROM domain_link_results

INNER JOIN sub_link_results
        ON domain_link_results.word = sub_link_results.word

WHERE domain_link_results.word = "national"

GROUP BY domain_link_results.word

另一方面，最好在同一个表中包含所有链接，并使用额外的字段来确定它是域链接还是子链接。在不了解您的系统的情况下，很难说。

如何在单个查询中的单个行中显示单个字段的多个值？

1 个答案: