SQL query with one to many relation - sql

Question

I have following table
Table1
id name col1 col2 col3 col4
-----------------------------------
1 test 1.1 1.2 1.3 1.4
2 test2 2.1 2.2 2.3 2.4
Table2
id fk_table1 amt type(fk_table3)
-----------------------------------
1 1 2 1
2 1 3 1
3 1 9 2
4 2 1 1
and I want to query such that I have get below result
id | name | total_type1_amt |total_type2_amt | col1 col2 col3 col4
-----------------------------------------------------------------------
1 test 5 (2+3) 9 1.1 1.2 1.3 1.4
2 test2 1 0 2.1 2.2 2.3 2.4
Basically in result I want group by table1.id with added columns for total_typeX_amt, there will be millions of rows in table1 and table2 so basically looking for optimized way to do it.

Answer 1

SELECT t1.id,
t1.name,
t2.total_type1_amt,
t2.total_type2_amt
FROM table1 t1
INNER JOIN
(
SELECT fk_table1,
SUM(CASE WHEN type = 1 THEN amt END) AS total_type1_amt,
SUM(CASE WHEN type = 2 THEN amt END) AS total_type2_amt
GROUP BY fk_table1
) t2
ON t1.id = t2.fk_table1
If you need this to run fast, you can try creating a view using the subquery (which I called t2 above), with an index on the fk_table1 column. Assuming that table1 also has an index on id, then the join should run reasonably fast.

Answer 2

It's not 100% your desired result, but you could try something like
select fk_table1, type, sum(amt)
from table1
inner join table2 on table1.id = table2.fk_table1
group by fk_table1, type
which should lead to something like
fk_table1 | type | sum
1 1 5
1 2 9
2 1 1

Answer 3

try dis to get total for total_type1_amt
select table1.id, table2.name ,(select count(table2.amt) as total_type1_amt where table1.id = table2.fk_table1 from table.1) from table1
inner join table2 on table1.id = table2.fk_table1
group by table.id

Answer 4

SELECT
T1.id,
T1.name,
SUM(CASE T2.type WHEN 1 THEN T2.amt ELSE 0 END) AS total_type1_amt,
SUM(CASE T2.type WHEN 2 THEN T2.amt ELSE 0 END) AS total_type2_amt
FROM #tbl1 T1
LEFT JOIN #tbl2 T2 ON T1.id=T2.fk_table1
GROUP BY T1.id,T1.name
Output:

Answer 5

You can try like this
;WITH cte
AS (SELECT
fk_table1, SUM([1]) total_type1_amt, COALESCE(SUM([2]), 0) total_type2_amt
FROM #table1 PIVOT (MAX(amt) FOR type IN ([1], [2])) p
GROUP BY fk_table1)
SELECT
t.id, t.name, c.total_type1_amt, c.total_type2_amt
FROM #table1 t
LEFT JOIN cte c
ON t.id = c.fk_table1

Answer 6

There at least 2 ways:
SELECT t1.id,
t1.name,
COALESCE(SUM(CASE WHEN [type] = 1 THEN amt END),0) AS total_type1_amt,
COALESCE(SUM(CASE WHEN [type] = 2 THEN amt END),0) AS total_type2_amt,
col1,
col2,
col3,
col4
FROM table1 t1
LEFT JOIN table2 t2
ON t1.id = t2.fk_table1
GROUP BY t1.id, t1.name, col1, col2, col3, col4
Another:
SELECT *
FROM (
SELECT t1.id,
t1.name,
t2.[type],
SUM(t2.amt) as sum
FROM table1 t1
LEFT JOIN table2 t2
ON t1.id = t2.fk_table1
GROUP BY t1.id, t1.name, t2.[type]
) as t
PIVOT (
MAX(sum) FOR type IN ([1],[2])
) as pvt