I don't remember the specific case (it's been a few years) but I do remember it had something to do with updating an array member. I googled around and found th

I don't remember the specific case (it's been a few years) but I do remember it had something to do with updating an array member. I googled around and found this [0] (the second question) which looks very similar. It's as simple as it gets - find an array member with "value" equal to "blue" and decrease its "qty". In MongoDB you can do that pretty easily ([1]) and the update should be atomic. The SQL version looks complicated and it's not even the form that you should use (notice the note about the race condition). Then again, maybe there's already a way to do that in PostgreSQL in a more elegant way, I assume the support has improved over the years. [0] https://dba.stackexchange.com/questions/193390/update-nth-element-of-array-using-a-where-clause https://dba.stackexchange.com/questions/193390/update-nth-el... [1] https://gist.github.com/jiripospisil/36f37a41f9b2c7fe74e841eb064be9d7 https://gist.github.com/jiripospisil/36f37a41f9b2c7fe74e841e...