SELECT MIN("Bangladeshi Population") FROM table_22845 WHERE "Rank" = '7'
How many Bangladeshi citizens are there in the borough ranked at number 7?
CREATE TABLE table_22845 (
    "Rank" real,
    "London Borough" text,
    "Indian Population" real,
    "Pakistani Population" real,
    "Bangladeshi Population" real,
    "Chinese Population" real,
    "Other Asian Population" real,
    "Total Asian Population" real
)