If you understand SQL enough to know if the query ChatGPT produced is valid - you probably could have written it yourself. I don’t see how prompting chatgpt and testing its results is faster or better than just writing SQL.
I can recognize much more faces than I can describe/draw. It is easier to read foreign language than to write it (active vs passive vocabulary).
It is the same with googling, looking for a solution on StackOverflow: understanding/judging whether the solution is good may be faster than constructing it yourself.
Imo it depends on what you're prompting. If you yourself do not fully understand what you want and/or which information you have to provide for the model to 'understand' enough context, prompts will not give good results.
I usually find ChatGPT very good for converting conceptual ideas to a concrete piece of 'boilerplate' to work off of. It can help you jump gaps in your proces, but in the end you still have to make the jumps yourself.
You test it.
And what do you mean by “know SQL?” No one knows everything about SQL. Virtually everyone writing SQL is in between the two extreme cases you provide.