Building a single table from different data sets

Hello,

I'm trying to build a single table from different data sets. This is because the needed queries can't be preformed at the same time. I noticed that I can't pull in fields from different queries and I'm not sure why. Can someone speak on this?

-Will

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Virgil Dodson

Hi Will, have you tried to use the Joint data set to combine your two data sets together? If you look at the Binding tab in the table property, you will see that it is bound to a particular data set. This will be the default binding for individual data items. To get around this, change the data binding for your particular data item. Depending on your needs, you could alsol try embedding a second table within the first.

shepherr

Hello,
I puzzled over this as well and found that for me the best solution was to write the sql needed to combine the data in one data set. At first I thought it couldn't be done - and I did end up with some 400 line sql statements - but they work very well.

As far as I know joint data sets only allow you to join 2 data sets. I've never tried building a joint data set out of other data sets if you have more than 2 data sets you want to combine

The question I have is if you use a joint data set does it combine the sql before it's sent to the server or are separate sql statements sent to the server then combine at the client. If the later is the case maybe that's another reason to pack everything into one sql - let the server do the work - not the client...
Hope this helps...

mwilliams

shepherr,

A single joint dataSet does only join 2 dataSets. However, you can join a joint dataSet with another dataSet, so you're not just limited to 1 join.

To answer your question on how BIRT does a join, each query is run and then the result sets are joined. The SQL is not joined before the query is run.