Last time it was useful I re-implemented XIRR(https://support.microsoft.com/en-us/office/xirr-function-de1242ec-6477-445b-b11b-a303ad9adc9d https://support.micr

Last time it was useful I re-implemented XIRR(https://support.microsoft.com/en-us/office/xirr-function-de1242ec-6477-445b-b11b-a303ad9adc9d https://support.microsoft.com/en-us/office/xirr-function-de1...) using Excel's approach in pure SQL so it would be able to make the finance bros happy, it was something like 50,000x faster than the user defined function/loop approach.