Both have classes that you can take,but in a nut shell this is what I can tell you about it.
A live Report is a livelink object that knows how to query the livelink database. If you sign a NDA with OT you will get a free schema guide that shows you the relations.It is not proper for me to give too much about livelink schema,but as almost everybody in the livelink forum know dtree is a important table and you could write select * from dtree where subtype=144 and put that in a LR object and it will show you the results.Look at the canned livereports available and that is how you start doing it. The livelink database is NOT TO BE MANIPULATED DIRECTLY BY SQL. The only way perhaps if you do not have programming resources to change things en masse in livelink is by buying WebReports. OT producse LAPI,webservices and oscript to do manipulation by customers.
A webreport amongst MANY MANY OTHER THINGS IN ITS ANVIL has a extremely huge tag library that users with sql prowess can use to change things as well.A webreport actually can call a Livereport and using javascript logic and tag library logic that resonate has produced you can acheive certain things with it.For e.g you may want to show clickable things,send email,output a excel file etc etc that is not possible with livereports. WR's can almost have anything as its source,it is very versatile in that aspect.
The best thing for you to do is basically work with the module and read its documentation or take training.
I am of the opinion that very complex things you should not try to do with webreports. What may take you a few lines of code may look like crazy code when you look at webreports.Given a choice and the customet allowed me to program in lapi,socript or websvcs I may take that route if it was a very complex requiremnt.But for actual report generation in livelink and other databases WR has no equal.
Well, if I called the wrong number, why did you answer the phone?
James Thurber, New Yorker cartoon caption, June 5, 1937
Certified OT Developer,Livelink ECM Champion 2008,Livelink ECM Champion 2010