sql_gen.py: Join.to_str(): Fixed bug where USING should be used if all columns are join_same_not_null, rather than join_same, because USING uses plain = for comparison. sql.py: put_table(): input_joins now can use sql_gen.join_same_not_null in order to use USING syntax.
sql_gen.py: Join.to_str(): Fixed bug where USING should be used if all columns are join_same_not_null, rather than join_same, because USING uses plain = for comparison. sql.py: put_table(): input_joins now can use sql_gen.join_same_not_null in order to use USING syntax.