add new usage: use cik_dt only to merge rather than (cik_dt,cik_iid)

[sn0wfree]

ClickSQL/ClickSQL/factor_table/__init__.py

Line 182 in 42906c3

sql = f"select * from ({sql1}) all full join ({sql2}) using (cik_dt,cik_iid) {settings}"

add new usage: use cik_dt only to merge rather than (cik_dt,cik_iid)
when join two sql, but join column is only cik_dt or cik_iid.
such as:

sql = f"select * from ({sql1}) all full join ({sql2}) using (cik_dt)  {settings}" 

or

sql = f"select * from ({sql1}) all full join ({sql2}) using (cik_iid)  {settings}"