The question is if the Mac Mini will use the same CPU as the iPad Pro (likely) and the same clockspeed (probably), and if the cooling will be similar (likely). If the Mac Mini has a larger thermal envelope, it will be faster for high loads. However, since SQLite is I/O constrained, I expect performance to be completely determined by the speed of the DRAM and the SSD, which might be better specs as the iPad Pro but are likely the same.