I have one 'MainTable'(1) as , one 'dispatched table'(2) and 'dispatchedbutNotOrdered'(3).
NOTE: table one is updated with 50K records each day and also there is no primary key.
In dispatchedButNotOrdered(3) table I have to insert those cards which are present in dispatched table(2) but not in MainTable(1). so to do that updation which is faster in terms of performance - Inner join, left join or if exist?
Right now I am using Join and it is taking 3 hrs or more and CPU utilisation is 100%, how can i reduce that?
There is one common field let say account number, Can someone put down a query for above?