Counting one field of table in other table - sql

Question

I wrote a script in oracle. But it does not give me the result that i want.
I need this one, imagine i have two table. Order_table and book table.
My order table is like this
ORDER_TABLE Table
ID TYPE_ID VALUE_ID
1 11 null
2 11 null
3 11 null
4 12 null
5 11 null
Book Table
ID ORDER_TYPE DELETED
1 1 F
2 null F
3 5 F
4 5 F
5 4 F
6 4 F
7 3 T
My script is like this
Select *
From (
Select Newtable.Counter As Value_id,
o.Id As Id,
o.Type_id As Type_id
From (
Select (Count B.Order_Type) As Counter,
B.Order_Type As Id
From Book B
Where B.Deleted = 'F'
Group By B.Order_Type
Order By Count(B.Order_Type) Desc
) newtable,
order_table o
where o.id = newtable.id
and o.type_id = 11
)
order by id asc;
Result is like this.
Value_ID TYPE_ID ID
2 11 5
2 11 4
1 11 1
It is not showing that second and third id has 0 count, Have can i show 0 count too ?
Result should be like this.
Value_ID TYPE_ID ID
2 11 5
2 11 4
1 11 1
0 11 2
0 11 3

Answer 1

First, do not use implicit JOIN syntax(comma separated), that's one of the reason this mistakes are hard to catch! Use the proper JOIN syntax.
Second, your problem is that you need a left join, not an inner join , so try this:
Select *
From (Select coalesce(Newtable.Counter,0) As Value_id,
o.Id As Id,
o.Type_id As Type_id
From order_table o
LEFT JOIN (Select Count(B.Order_Type) As Counter, B.Order_Type As Id
From Book B
Where B.Deleted = 'F'
Group By B.Order_Type
Order By Count(B.Order_Type) Desc) newtable
ON(o.id = newtable.id)
WHERE o.type_id = 11)
order by id asc;

Answer 2

Oracle Setup:
CREATE TABLE order_table ( id, type_id, value_id ) AS
SELECT 1, 11, CAST( NULL AS INT ) FROM DUAL UNION ALL
SELECT 2, 11, CAST( NULL AS INT ) FROM DUAL UNION ALL
SELECT 3, 11, CAST( NULL AS INT ) FROM DUAL UNION ALL
SELECT 4, 12, CAST( NULL AS INT ) FROM DUAL UNION ALL
SELECT 5, 11, CAST( NULL AS INT ) FROM DUAL;
CREATE TABLE book ( id, order_type, deleted ) AS
SELECT 1, 1, 'F' FROM DUAL UNION ALL
SELECT 2, NULL, 'F' FROM DUAL UNION ALL
SELECT 3, 5, 'F' FROM DUAL UNION ALL
SELECT 4, 5, 'F' FROM DUAL UNION ALL
SELECT 5, 4, 'F' FROM DUAL UNION ALL
SELECT 6, 4, 'F' FROM DUAL UNION ALL
SELECT 7, 3, 'T' FROM DUAL;
Query:
SELECT COUNT( b.order_type ) AS value_id,
o.id,
o.order_type
FROM order_table o
LEFT OUTER JOIN
book b
ON ( o.id = b.order_type AND b.deleted = 'F' )
WHERE o.type_id = 11
GROUP BY o.id, o.type_id
ORDER BY value_id DESC, id DESC;
Output:
VALUE_ID ID TYPE_ID
-------- -- -------
2 5 11
1 1 11
0 3 11
0 2 11
However, if you did want to use the legacy Oracle comma-join syntax then you can get the same result with:
SELECT COUNT( b.order_type ) AS value_id,
o.id,
o.order_type
FROM order_table o,
book b
WHERE o.type_id = 11
AND b.order_type (+) = o.id
AND b.deleted (+) = 'F'
GROUP BY o.id, o.type_id
ORDER BY value_id DESC, id DESC;
But please don't as the ANSI/ISO joins are much easier to comprehend the join conditions.

Answer 3

You could also do this with a scalar subquery, which may or may not be more performant than the left join versions described in the other answers. (Quite possibly, the optimizer may rewrite it to be a left join anyway!):
with order_table ( id, type_id, value_id ) as (select 1, 11, cast( null as int ) from dual union all
select 2, 11, cast( null as int ) from dual union all
select 3, 11, cast( null as int ) from dual union all
select 4, 12, cast( null as int ) from dual union all
select 5, 11, cast( null as int ) from dual),
book ( id, order_type, deleted ) as (select 1, 1, 'F' from dual union all
select 2, null, 'F' from dual union all
select 3, 5, 'F' from dual union all
select 4, 5, 'F' from dual union all
select 5, 4, 'F' from dual union all
select 6, 4, 'F' from dual union all
select 7, 3, 'T' from dual)
-- end of mimicking your tables; you wouldn't need the above subqueries as you already have the tables.
-- See SQL below:
select (select count(*) from book bk where bk.deleted = 'F' and bk.order_type = ot.id) value_id,
ot.type_id,
ot.id
from order_table ot
order by value_id desc,
id desc;
VALUE_ID TYPE_ID ID
---------- ---------- ----------
2 11 5
2 12 4
1 11 1
0 11 3
0 11 2