>It doesn't mean I recommend to keep your current UPDATE command as is. I'd rather re-format it to MERGE and to simplify its meaning.

Yes, but, the execution plan changed from 96% allocated to those two previous select to 1% after the COALESC syntax.

I am testing now the time it takes for this 30 minutes benchmark as previously taken with the version not included this syntax (the one which simply used NoProvince=84).

The first two runs with the dual selects took longer than an hour so I stopped it.