SQL查询多个表，具有多个连接和逗号分隔列表的列字段

2022-01-09 00:00:00 join arrays sql mysql coldfusion

我有一个查询，我在其中连接三个单独的表(节点、控件、服务).

I have a query where I join three separate tables (node, control, service).

下面是它们的列标题和示例数据.

Below is their column headings and sample data.

NODE TABLE (contains over 7000 rows) nodeID | host | serviceID | controlID 1 | server1 | 1,2,3,4,9,50,200 | 1 2 | server2 | 2,3,4,9,200 | 2 3 | server3 | 1,2,3,4,9,50,200 | 2 4 | server4 | 1,2,50,200 | 3 5 | server5 | 1,4 | 3 CONTROL TABLE (contains roughly 50 rows) controlID | name 1 | Control Name One 2 | Control Name Two 3 | Control Name Three 4 | Control Name Four 5 | Control Name Five SERVICE TABLE (contains roughly 3000 rows) serviceID | name 1 | Service Name One 2 | Service Name Two 3 | Service Name Three 4 | Service Name Four 5 | Service Name Five 6 | Service Name Six 50 | Service Name 50 200 | Service Name 200

如您所见，除了 node.serviceID 列之外，数据库表有一些规范化.我完全同意 node.serviceID 应该被规范化并创建一个一对多的数据透视表.那里没有争论.但是，我不控制将信息插入数据库的脚本.我只能从表格中读取数据并尽可能地格式化数据.

As you can see, the database tables have a bit of normalization with the exception of the node.serviceID column. I whole heartily agree that node.serviceID should be normalized and a pivot table of one-to-many created. No argument there. However, I do not control the scripts that insert the information into the database. I can only read from the tables and format the data how I can.

所以，下面是我编写的 SQL 查询，它确实有效，但正如预期的那样，node.serviceID 不能很好地与 service.serviceID 结合.请注意，我在最终查询中没有使用 SELECT *，我从节点表中选择了大约 20 个字段，并且不想使查询更加混乱.下面只是一个例子.

So, below is the SQL query I wrote that does work but the, as expected, node.serviceID does not join well with service.serviceID. Please note that I am not using a SELECT * in my final query, I select about 20 fields from the node table and do not want to make the query more confusing. Below is just an example.

SELECT * FROM node AS a LEFT JOIN control AS b ON a.controlID = b.controlid LEFT JOIN service AS c ON a.serviceID = c.serviceId ORDER BY a.host

上面的查询吐出了类似的东西:

The query above spits out something similar:

Host Control Services server1 Control Name One 1,2,3,4,9,50 server2 Control Name Three 1,2,9,50 server3 Control Name Two 4 server4 Control Name Four 1,2,3,4,9 server5 Control Name Two 1,2,3,50 server6 Control Name Five 1,3,4,9,50

我要找的是这个:

Host Control Services server1 Control Name One Service Name One, Service Name Two, Service Name Three, Service Name Four, Service Name Nine, Service Name Fifty server2 Control Name Three Service Name One, Service Name Two, Service Name Nine, Service Name Fifty server3 Control Name Two Service Name Four server4 Control Name Four Service Name One, Service Name Two, Service Name Three, Service Name Four, Service Name Nine

我已经在 stackoverflow.com 上搜索了遇到此类问题的人，但我只能找到在 ID 和名称上加入多个表或扩展 ID 列表但不能同时扩展的人.

I have scoured stackoverflow.com for someone with an issue like this but I can only find either joining multiple tables on ID and name OR someone expanding a list of IDs but not both together.

这个接近了:使用逗号分隔的 sql id 但不完全.

This one came close: Using id that are comma separated sql but not quite.

我已经尝试了使用 ListToArray() 的各种 CFML 方法，并尝试使用索引对它们进行循环，但对我来说没有任何用处.

I have tried various methods of CFML with ListToArray() and tried looping over them with an index but nothing would work for me.

我从中获取数据的服务器是 MySQL 5.1，我使用 jQuery 和 ColdFusion (Railo 4.2) 的组合来格式化数据.

The server I snag the data from is MySQL 5.1 and I am using a combination of jQuery and ColdFusion (Railo 4.2) to format the data.

这是我第一次在stackoverflow上发帖，如果真的有答案，我很抱歉，我没有搜索足够长的时间，并且会重复这个问题.

This is my first time posting on stackoverflow, so my apologies if there really is an answer to this, I did not search long enough, and would make this question a duplicate.

----------------- 更新 --------------------

----------------- UPDATE --------------------

我尝试了 Leigh 建议的查询和 CFML.

I tried the query and CFML suggested by Leigh.

所以，我得到以下信息:

So, I get the following:

server1 服务名一服务名一服务名一服务名一服务名一服务名一服务名一服务名二服务名二服务名二服务名二服务名二、服务名称二、服务名称三、服务名称四、服务名称四、服务名称四、服务名称四、服务名称四、服务名称四、服务名称四

server1 Service Name One , Service Name One , Service Name One , Service Name One , Service Name One , Service Name One , Service Name One , Service Name Two , Service Name Two , Service Name Two , Service Name Two , Service Name Two , Service Name Two , Service Name Three , Service Name Four , Service Name Four , Service Name Four , Service Name Four , Service Name Four , Service Name Four , Service Name Four

在这一点上，我不确定这是否只是 CFML 或 SQL 查询中的一些变化.但是，它看起来确实很有希望.

I am not sure, at this point, if that is just a little bit of change with the CFML or something in the SQL query. But, it does look promising.

推荐答案

如果你真的不能修改表结构，你能做的最好的可能是旧的列表黑客之一:

If you really cannot modify the table structure, probably the best you can do is one of the old list hacks:

使用 JOIN 和 FIND_IN_SET(value, commaSeparatedString)

SELECT n.Host, c.Name AS ControlName, s.Name AS ServiceName从节点 nLEFT JOIN control c ON c.controlID = n.controlIDLEFT JOIN service s ON FIND_IN_SET(s.serviceID, n.serviceId)ORDER BY n.host, s.Name;

使用 LIKE 检测节点列表中是否存在特定的 serviceID 值

Use LIKE to detect the presence of a specific serviceID value within the node list

SELECT n.Host, c.Name AS ControlName, s.Name AS ServiceName从节点 nLEFT JOIN control c ON c.controlID = n.controlIDLEFT JOIN 服务开启CONCAT(',', n.serviceID,',') LIKECONCAT('%,', s.serviceID,',%')ORDER BY n.host, s.Name;

SQLFiddle

但是，正如您已经指出的那样，该列确实应该标准化.虽然上述方法应该适用于小型数据集，但它们会遇到使用列表"的常见问题.这两种方法都不是非常友好的索引，因此不能很好地扩展.此外，两者都执行字符串比较.所以最细微的差别都可能导致匹配失败.例如，1,4 将匹配两个 serviceID，而 1,(space)4 或 1,4.0 将仅匹配一个.

However, as you already noted that column really should be normalized. While the methods above should work for small data sets, they suffer from the usual problems of working with "lists". Neither method is very index friendly, and as a result, will not scale well. Also, both perform string comparisons. So the slightest difference may cause the matching to fail. For example, 1,4 would match two serviceID's, whereas 1,(space)4 or 1,4.0 would match only one.

根据评论更新:

在第二次阅读时，我不确定上述内容是否能准确回答您提出的问题，但它应该为您提供良好的合作基础......

On second read, I am not sure the above answers the precise question you are asking, but it should provide a good basis to work with ...

如果您不再需要 CSV 列表，只需使用上述查询之一并照常输出各个查询列.结果将是每行一个服务名称，即:

If you no longer want a CSV list, just use one of the queries above and output the individual query columns as usual. The result will be one service name per row, ie:

server1 | Control Name One | Service Name 200 server1 | Control Name One | Service Name 50 ..

否则，如果您需要保留逗号分隔值，一种可能性是在查询结果上使用 .由于结果首先按主机"排序，因此类似于下面的代码.注意:要使组"正常工作，结果必须按 Host 排序，并且必须使用多个 cfoutput 标签，如下所示.
Otherwise, if you need to preserve the comma separated values, one possibility is to use a <cfoutput group=".."> on the query results. Since the results are ordered by "Host" first, something like the code below. NB: For "group" to work properly, the results must be ordered by Host and you must use multiple cfoutput tags as shown below. <cfoutput query="..." group="Host"> #Host# | #ControlName# | <cfoutput> #ServiceName#, </cfoutput> <br> </cfoutput> 结果应该是这样的: server1 | Control Name One | Service Name 200, Service Name 50, Service Name Four, Service Name One, Service Name Three, Service Name Two, server2 | Control Name Two | Service Name 200, Service Name Four, Service Name Three, Service Name Two, server3 | Control Name Two | Service Name 200, Service Name 50, Service Name Four, Service Name One, Service Name Three, Service Name Two, server4 | Control Name Three | Service Name 200, Service Name 50, Service Name One, Service Name Two, server5 | Control Name Three | Service Name Four, Service Name One, 更新 2: 我忘记了 MySQL 中 cfoutput group 有一个更简单的替代方法:GROUP_CONCAT I forgot there is a simpler alternative to cfoutput group in MySQL: GROUP_CONCAT <cfquery name="qry" datasource="MySQL5"> SELECT n.Host, c.Name AS ControlName, GROUP_CONCAT(s.Name) AS ServiceNameList FROM node n LEFT JOIN control c ON c.controlID = n.controlID LEFT JOIN service s ON FIND_IN_SET(s.serviceID, n.serviceId) GROUP BY n.Host, c.Name ORDER BY n.host </cfquery>

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