RQDA -导出项目中每个文件的类别

Question

我已经在RQDA中编写了许多文本，我正在尝试导出数据库中的类别。我希望最终的结果是一个数据帧，如下所示：

Files   Categories
File1   Category1
File2   Category2
File3   Category3
File4   Category2
File5   Category1

我尝试了下面的代码，它是我从这里改编的Rblogger

categories <- RQDAQuery("select filecat.name as category, source.name as filename 
                         from treefile, filecat, source 
                         where treefile.catid=filecat.catid and treefile.fid=source.id and treefile.status=1")

但到目前为止，它已经产生了一个空文件：

str(categories)
'data.frame':   0 obs. of  2 variables:
 $ category: chr 
 $ filename: chr 

> dim(categories)
[1] 0 2
> summarise(categories)
data frame with 0 columns and 1 row

欢迎任何帮助。

Answer 1

一个旧电子邮件列表中的一些朋友非常友好地帮助了我，所以答案如下：

codings <-RQDAQuery("select s.name as 'filename', f.name as 'codes' from source s, 
                   coding c, 
                   freecode f where s.id = c.fid and c.cid = f.id and s.status = 1 order by s.name")

categories <- RQDAQuery("select s.name as 'filename', 
                    co.name as 'categories' from source s, 
                    coding c, freecode f, codecat co, 
                    treecode tr where s.id = 
                    c.fid and c.cid = f.id and co.catid = 
                    tr.catid and tr.cid = f.id and s.status = 1 and c.status = 1 and 
                    f.status = 1 order by s.name")

万事如意