For me, the first day at the office consists of analysing two databases with the same schema, just different data. I need to figure out if these two can be combined into one schema, where we can apply Row Level Security to separate the data again. Most tables will be easily merged, because the primary key ranges are a lot apart from eachother, but some tables have similar data, where I must check if this is a problem and if it is, I will have to write a merger script.
The nice thing though is that when they started the second database they already knew that one day it should all be merged into a single database, so the sequence range for both databases is a lot apart. That should simplify the merging, but I do need to do a lot of checking. Hopefully I can generate some checks or do some smart sql ;-).