SQL Server查询联接两个表

Question

I have two tables here

Table 1 :

NAME      |MED_TYPE |MED_STATUS  |DAYS
----------|---------|------------|--------
miyo      |1b       |APPROVED    |0.5
miya      |1b       |APPROVED    |1.0
jun       |3b       |APPROVED    |1.0
kite      |3b       |APPROVED    |1.0
hans      |1b       |APPROVED    |1.0
mark      |1b       |APPROVED    |2.0
jep       |1b       |APPROVED    |1.0
Gali      |2b       |APPROVED    |0.5
Hera      |1b       |APPROVED    |0.5
Zues      |2b       |APPROVED    |0.5

Table 2 :

STUDENT |MED_TYPE|REMAINING_MED|ACTIVE
--------|--------|-------------|------
miko    |3b      |1.0          |1
kite    |1b      |6.0          |1
kite    |2b      |9.5          |1
kite    |2b      |1.0          |1
jun     |1b      |10.0         |1
arri    |1b      |8.5          |1
arri    |2b      |9.5          |1
arri    |3b      |1.0          |1
imko    |1b      |6.5          |1
miko    |2b      |8.0          |1

With this query:

SELECT
    NAME,
    SUM(CASE
           WHEN MED_TYPE = '1b' AND MED_STATUS = 'APPROVED' 
              THEN DAYS
              ELSE 0
        END) AS USED_1b,
    SUM(CASE
           WHEN MED_TYPE = '2b' AND MED_STATUS = 'APPROVED' 
              THEN DAYS
              ELSE 0
        END) AS USED_2b
FROM 
    table1
GROUP BY 
    NAME

I get the following results:

STUDENT   |USED_1b|USED_2b
----------|-------|-------
abe       |3.5    |5.0
arri      |1.5    |0.5
kiko      |0.0    |0.0
chen      |4.0    |0.5
heli      |0.5    |0.0
miyo      |6.5    |5.5
mika      |2.0    |1.0
jun       |3.0    |3.0
jake      |2.5    |2.5
zues      |3.5    |2.5

but I want to get the following:

NAME | USED_1b | USED_2b | REMAINING_1b | REMAINING_2b

remaining_1b and remaining_2b will be coming from table 2 column remaining_med , they can be categorized with med type. What connects the two tables is the name and student. Also I want to check if the student is active or not. If not active it won't be displayed in the result table.

What will be the right query for this? I don't know what to use join or union. I'm pretty new to SQL Server.

BTW, the tables 1 and 2 and the results are just partial of the whole table. It will be too long if I post all here.

Answer 1

You can find sums separately and then join.

Like this:

select t1.name,
    t1.USED_1b,
    t1.USED_2b,
    t2.remaining_1b,
    t2.remaining_2b
from (
    select name,
        SUM(case when MED_TYPE = '1b'
                    and MED_STATUS = 'APPROVED' then DAYS else 0 end) as USED_1b,
        SUM(case when MED_TYPE = '2b'
                    and MED_STATUS = 'APPROVED' then DAYS else 0 end) as USED_2b
    from table1
    group by name
    ) t1
join (
    select student,
        SUM(case when MED_TYPE = '1b' then remaining_med else 0 end) as remaining_1b,
        SUM(case when MED_TYPE = '2b' then remaining_med else 0 end) as remaining_2b
    from table2
    group by student
    ) t2 on t1.name = t2.student;