Re: A 3 table join question

On Fri, Aug 16, 2019 at 12:30:33PM -0700, Ken Tanzer wrote:
> On Fri, Aug 16, 2019 at 7:24 AM rob stone <floriparob(at)gmail(dot)com> wrote:
>
> > Hello,
> >
> > On Fri, 2019-08-16 at 07:39 -0400, stan wrote:
> > > What am I doing wrong here?
> > >
> >
> >
> > Your view assumes that all three "streams" contain all the proj_no's
> > whereas your test data for expense_report_cost_sum_view has no proj_no
> > = 764.
> >
> >
> Hi. I'm probably missing something, but it seems simpler to either join
> with USING, or by COALESCEing the two ID fields in left part of the JOIN
> clause (COALESCE(t1.proj_no,t2.proj_no)=t3.proj_no).
>
> Cheers,
> Ken
>
> CREATE TEMP TABLE t1 (id int, t1_val TEXT);
> INSERT INTO t1 VALUES (2,'T1_2');
> INSERT INTO t1 VALUES (5,'T1_5');
> INSERT INTO t1 VALUES (7,'T1_7');
> INSERT INTO t1 VALUES (10,'T1_10');
>
> CREATE TEMP TABLE t2 (id int, t2_val TEXT);
> INSERT INTO t2 VALUES (3,'T2_3');
> INSERT INTO t2 VALUES (5,'T2_5');
> INSERT INTO t2 VALUES (6,'T2_6');
> INSERT INTO t2 VALUES (10,'T2_10');
>
> CREATE TEMP TABLE t3 (id int, t3_val TEXT);
> INSERT INTO t3 VALUES (4,'T3_4');
> INSERT INTO t3 VALUES (6,'T3_6');
> INSERT INTO t3 VALUES (7,'T3_7');
> INSERT INTO t3 VALUES (10,'T3_10');
>
> SELECT id,t1_val,t2_val,t3_val
> FROM
> t1
> FULL JOIN t2 USING (id)
> FULL JOIN t3 USING (id)
> ;
>
> SELECT COALESCE(t1.id,t2.id,t3.id) AS id,t1_val,t2_val,t3_val
> FROM
> t1
> FULL JOIN t2 ON (t1.id=t2.id)
> FULL JOIN t3 ON (COALESCE(t1.id,t2.id)=t3.id)
> ;
>
> id | t1_val | t2_val | t3_val
> ----+--------+--------+--------
> 2 | T1_2 | |
> 3 | | T2_3 |
> 4 | | | T3_4
> 5 | T1_5 | T2_5 |
> 6 | | T2_6 | T3_6
> 7 | T1_7 | | T3_7
> 10 | T1_10 | T2_10 | T3_10
> (7 rows)
>
OK, I am clearly not understanding this yet.

Here is what I am trying:

select
COALESCE(
labor_cost_sum_view.proj_no ,
material_cost_sum_view.proj_no ,
expense_report_cost_sum_view.proj_no
)
AS
proj_no ,
labor_cost_sum_view.labor_cost_sum ,
material_cost_sum_view.mtrl_cost ,
expense_report_cost_sum_view.burdened_cost ,
coalesce( labor_cost_sum_view.labor_cost_sum, 0)
+
coalesce(material_cost_sum_view.mtrl_cost, 0)
+
coalesce(expense_report_cost_sum_view.burdened_cost, 0)
from
labor_cost_sum_view
full join material_cost_sum_view on
material_cost_sum_view.proj_no = labor_cost_sum_view.proj_no
full join expense_report_cost_sum_view on
expense_report_cost_sum_view.proj_no = labor_cost_sum_view.proj_no
;

Having simplified things a bunch, and removing casts and aliases etc.

But here is what I am getting as a result set:

proj_no | labor_cost_sum | mtrl_cost | burdened_cost | ?column?
---------+----------------+-----------+---------------+----------------
45 | 3133.17500000 | 5394.6800 | 2564.980000 | 11092.83500000
764 | 810.75000000 | 7249.4800 | | 8060.23000000
789 | 7015.57500000 | | | 7015.57500000
7456 | | 4007.3000 | | 4007.3000
33 | | | 241.380000 | 241.380000
7456 | | | 1747.110000 | 1747.110000
(6 row

Note that project number 7456 appears in 2 rows.

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