如何从SQL中的两个表获取记录

Question

i have two DB tables STUDENT and FEES. Expected result is to get all record from table for particular month(date) with sum of amount in that month from FEES table and same id record from STUDENT table

STUDENT

FEES

**Expected result (for particular date according to DATE cloumn in FEE table ex : 02-2019 **

ID     NAME     ADDRESS     AMOUNT
-----------------------------------
S1     abc       ind        600
S2     pqr       ind        100

Answer 1

Use INNER JOIN .

Query

select t1.id, t1.name, t1.address, sum(t2.amount) as amount
from student as t1
join fess as t2
on t1.id = t2.id
group by t1.id, t1.name, t1.address;

Answer 2

Since you need results for a certain date, you don't need to group by date only by student:

select s.id, s.name, s.address, sum(f.amount) amount
from student s left join fees f 
on f.id = s.id
where f.date = '02-2019'
group by s.id, s.name, s.address;

See the demo . Results:

| id  | name | address | amount |
| --- | ---- | ------- | ------ |
| S1  | abc  | ind     | 600    |
| S2  | pqr  | ind     | 100    |

In your expected results the amount for id='S2' and date = '02-2019' should be 100 , right?