How to write the sql statement of the new view?

lanhuo3166

Take a column of View_a from Table A, a column of View_b from Table B, and a column of View_c from Table C. According to some conditions, the result of multiplying View_b and View_c is a new column NewView_bc. Now create a new view, the column names of the view are obtained from the above: View_a, View_b, NewView_bc. How to write the sql statement of the new view?

cv4bf5d65fd

create view view_name
as

select a.View_a, b.View_b, b.View_b * c.View_c NewView_bc
from Table A a, Table B b, Table C c
where a.id = b.id and a.id = c.id

go

lanhuo3166

I encountered a new problem:
    There is a view A with the following contents:
OrderID JeFen
2 11
2 16
2 270
8 112200
9 2460
9 240
I want to create a new view B to count A, so that the content of B is as follows:
OrderID JeFen
2 11 + 16 + 270
8 112200
9 2460 + 240
How to write the sql statement that generates view B?

26426613

create view B
as
select orderid, sum (jefen) sum_jefen
from a
group by orderid

cv4bf5d65fd

create view view B
as

select orderid, sum (jefen) JeFen
from view A
group by orderid