i was today years old when i learnt this about psql

i was running some sql queries and for some reason an aggregate function i was running was returning the number 0. this felt very strange since i kept looking at the command and it looked okay. so why was i getting 0?

so i decided to try simple calculation, SELECT 20 /100. 0. so after checking online i learnt that postgresql and sqlite databases discards the fraction part and only keeps the integer division. i have written window functions and recursive ctes but to think would have made me fail an interview is plainly embarrassing.

now i know