Question

Figured it out, solution below!

I have an HTML table that is being populated by data from a database with two tables using the following structure:

Table 1:
------------------------------
|id|data|other_data|more_data|
------------------------------

Table 2:
--------------------------------
|id|entryId|fileType|other_data|
--------------------------------

I’m joining these two tables similarly:

SELECT * FROM table1 LEFT JOIN table2 ON table2.entryId = table1.id

Sample return:

------------------------------------------------------------
|id|data|other_data|more_data|id|entryId|fileType|other_data|
-------------------------------------------------------------
|1 |....|..........|.........|1| 1      |file1   |..........|
|1 |....|..........|.........|2| 1      |file2   |..........|
|2 |....|..........|.........|3| 2      |file1   |..........|
|2 |....|..........|.........|4| 2      |file2   |..........|
|3 |....|..........|.........|5| 3      |file1   |..........|
|4 |....|..........|.........|6| 4      |file2   |..........|

For each case, I am expecting at least one result, usually two which I would like to sort based on the fileType field. fileType can either be file1 or file2.

<table>
<tr>
<td>file1 data here</td>
<td>file 2 data here</td>
</tr>
</table>

If there is no file1 or file 2 in the result, insert a dash (-), but always keep that table structured in the same way, and in the same order. How can I accomplish this? I tried a simple if/else construct, but my logic is wrong and returns the data out of order; I’m having trouble wrapping my head around a working solution.

while(docs.next) {

if(docs.getString("fileType").equals("file1")) {
        .....<td>file 1 data</td>
    }

else if(docs.getString("fileType").equals("file2")){
        .....<td>file 2 data</td>
    }
}

As always, your help is greatly appreciated!

**Figured it out, thanks! Solution:

I broke the logic into two queries then used what you suggest:
– first query grabs data from table1, sets up HTML table
– set two variables(fileData1, fileData2) null
– second query grabs data from table2, loops through the results to find matches and changes the actual value if the result exists
– after loop, print table cells with results**

Answer 1

If I understand correctly, you need to print both <td>s no matter what. Your if condition restricts printing <td> – it will print <td> only when the given condition is satisfied. So you need to alter it. Instead, you need to do this – read through docs, get fileType. If it is file1, assign value for that to a variable, that was initialized to null. If it is file2 , assign value for that to a variable, that was initialized to null. Then test for that variable and print either “-” or the content on each case.

Assuming variables file1Data and file2Data denotes string data from file1 and file2 respectively for each iteration over docs,

while(docs.next) {
   String file1Data = null;
   String file2Data = null;
   if(docs.getString("fileType").equals("file1")) {
   // assign value for fiel1Data here
   } 
   if(docs.getString("fileType").equals("file2")) {
   // assign value for fiel2Data here
   }
   System.out.println("<tr>");
   System.out.println("<td>" + (file1Data == null || file1Data.equals("")?"-" : file1Data) + "</td>");
   System.out.println("<td>" + (file2Data == null || file2Data.equals("")?"-" : file2Data) + "</td>");
   System.out.println("</tr>");
}