postgresql:postgresq创建空到100之间的随机整数

我想生成一个包含1000行数据的表

-- random int between `1-100` (including 1 and 100)
-- random int between `1-100` and also null (including 1 and 100)
-- random float between `0-100` (including 0 and 100)
-- random float between `0-100`and also null (including 0 and 100)
-- random Male (M) and Female (F) i.e M/F values
-- random Male (M) and Female (F) including null/empty i.e M/F values
-- random names of cities from a list (i.e newyork, london, mumbai, dubai etc)
-- random names of cities from a list including null/empty (i.e newyork, london, mumbai, dubai etc)

现在我知道了

create table foo as select random() as test,
from generate_series(1,1000) s(i);