I have two tables A and B with the same columns ID, Date, Main_id, Quantity. Main_id is a similar column for both the tables. I want to select ID, Date, a.quantity, b.quantity into table c.
A:
id | date | main_id | quantity_in
----------------------------------------------
12 4/10/2019 1 60
20 7/4/2019 2 30
33 9/6/2019 3 10
B:
id | date | main_id | quantity_out
----------------------------------------------
20 5/10/2019 1 10
40 7/4/2019 1 30
53 9/6/2019 1 10
C: result table
id | date | main_id | quantity_In | quantity_out
------------------------------------------------------------------
12 4/10/2019 1 60 null
20 5/10/2019 1 null 10
40 7/4/2019 1 null 30
53 9/6/2019 1 null 10
You seem to want union all:
select a.id, a.date, a.main_id, a.quantity_in, null as quantity_out
from a
where a.main_id = 1
union all
select b.id, b.date, b.main_id, null as quantity_in, b.quantity_out
from b
where b.main_id = 1;