BIRT: Align rows in list element - list

Question

I'm using the Birt list element to display my data from left to right. (see this question as reference). Eg. List element with a Grid in details and the grid set to inline.
The issue I'm facing now is, that the different rows in the grid are not aligned left to right (probably due to some rows having empty values in some fields). How can I force BIRT to align properly?
EDIT:
This is especially also a problem with longer text that wraps to more than 1 line. The wrapping /multiple lines should be reflected by all list elements in that "row of the output".

Answer 1

Unfortunately, I don't see any chance to accomplish this easily in the generic case - that is, if the number of records is unknown in advance, so you'd need more than one line:
student1 student2 student3
student4 student5
Let's call those line "main lines". One main line can contain up to 3 records. The number 3 may be different in your case, but we can assume it is a constant, since (at least for PDF reports) the paper width is restricted.
A possible solution could work like this:
In your data set, add two columns for each row: MAIN_LINE_NUM and COLUMN_NUM, where the meaning is obvious. For example, this could be done with pure SQL using analytic functions (untested):
select ...,
trunc((row_number() over (order by ...whatever...) - 1) / 3) + 1 as MAIN_LINE_NUM,
mod(row_number() over (order by ...whatever...) - 1), 3) +1 as COLUMN_NUM
from ...
order by ...whatever... -- The order must be the same as above.
Now you know where each record should go.
The next task is to transform the result set into a form where each record looks like this (for the example, think that you have 3 properties STUDENT_ID, NAME, ADDRESS for each student):
MAIN_LINE
STUDENT_ID_1
NAME_1
ADDRESS_1
STUDENT_ID_2
NAME_2
ADDRESS_2
STUDENT_ID_3
NAME_3
ADDRESS_3
You get the picture...
The SQL trick to achieve this is one that one should know.
I'll show this for the STUDENT_ID_1, STUDENT_ID_2 and NAME_1 column as an example:
with my_data as
( ... the query shown above including MAIN_LINE_NUM and COLUMN_NUM ...
)
select MAIN_LINE_NUM,
max(case when COLUMN_NUM=1 then STUDENT_ID else null end) as STUDENT_ID_1,
max(case when COLUMN_NUM=2 then STUDENT_ID else null end) as STUDENT_ID_2,
...
max(case when COLUMN_NUM=1 then NAME else null end) as NAME_1,
...
from my_data
group by MAIN_LINE_NUM
order by MAIN_LINE_NUM
As you see, this is quite clumsy if you need a lot of different columns.
On the other hand, this makes the output a lot easier.
Create a table item for your dat set, with 3 columns (for 1, 2, 3). It's best to not drag the dataset into the layout. Instead, use the "Insert element" context menu.
You need a detail row for each of the columns (STUDENT_ID, NAME, ADDRESS). So, add two more details rows (the default is one detail row).
Add header labels manually, if you like, or remove the header row if you don't need it (which is what I assume).
Remove the footer row, as you probably don't need it.
Drag the columns to the corresponding position in your table.
The table item should look like this now (data items):
+--------------+--------------+-------------+
+ STUDENT_ID_1 | STUDENT_ID_2 | STUDENT_ID3 |
+--------------+--------------+-------------+
+ NAME_1 | NAME_2 | NAME_3 |
+--------------+--------------+-------------+
+ ADDRESS_1 | ADDRESS_2 | ADDRESS_3 |
+--------------+--------------+-------------+
That's it!
This is one of the few examples where BIRT sucks IMHO in comparison to other tools like e.g. Oracle Reports - excuse my Klatchian.