每个类别的SQL计数

Question

I need to count rows based on 2 fields for grouping.

Animals (a)

id     group_id   strain_id     death_date     death_cause   status
-----------------------------------------------------------------------
1      512        164           2015-12-01     Culled        P
2      512        164           2015-12-02     Culled        A
3      512        164           2015-12-02     Surplus       B
4      512        230           2015-12-06     Culled        A
5      512        164           2015-12-28     Culled        A
6      512        230           2016-01-20     Culled        B
7      512        230           2016-01-20     Surplus       P
8      512        164           NULL           NULL          P
9      512        230           NULL           NULL          B
10     512        230           NULL           NULL          A
11     512        164           2016-01-25     Culled        B
12     512        164           2016-02-29     Culled        A
13     512        230           2016-02-03     Surplus       P
14     512        230           2016-02-03     Culled        A

Groups (g)

id     group_name
--------------
512    Mice

Strain (s)

id     strain_name
----------------
164    Strain 1
230    Strain 2

Group Animal Count (gac)

id     total_animals      alive_count       dead_count
----------------------------------------------------------------------
512    14                 3                 11

Mating History (mh)

id     animal_id     history_type      history_date
--------------------------------------------------------
1001   2             MA                2015-11-20
1002   2             MR                2015-12-01
1003   3             MA                2015-12-01
1004   6             FA                2015-12-21
1005   9             FA                2016-02-07
1006   10            MA                2016-01-27
1007   11            FA                2015-12-12

So when I group them by the strain_id and the death_cause this is what they should look like visually:

Strain 1 ---- Culled

1      512        164           2015-12-01     Culled        P
2      512        164           2015-12-02     Culled        A
5      512        164           2015-12-28     Culled        A
11     512        164           2016-01-25     Culled        B
12     512        164           2016-02-29     Culled        A

Strain 1 ---- Surplus

3      512        164           2015-12-02     Surplus       B

Strain 2 ---- Culled

4      512        230           2015-12-06     Culled        A
6      512        230           2016-01-20     Culled        B
14     512        230           2016-02-03     Culled        A

Strain 2 ---- Surplus

7      512        230           2016-01-20     Surplus       P
13     512        230           2016-02-03     Surplus       P

What I want to get from the SQL query is the following result:

g_name  s_name    d_cause  a_total  c_alive  c_dead  c_pup  c_breeder  c_total
------------------------------------------------------------------------------
Mice    Strain 1  Culled   12       3        9       1      2          5
Mice    Strain 1  Surplus  12       3        9       0      1          1
Mice    Strain 2  Culled   12       3        9       0      1          3
Mice    Strain 2  Surplus  12       3        9       2      0          2

Basically I want to count the number of animals using 2 categories which in this case is the strain_name and the death_cause

Note that for an animal to be counted as a breeder ( c_breeder ), I have to look at the Mating History table and check if the animal_id has ever had any of these codes MA or FA .

I am using INNER JOIN on the groups , group_animal_count , and strains . I use LEFT JOIN for mating_history since animals with a status of P won't have records in that table since they're just pups and won't be involved with mating.

Answer 1

Try:

SELECT group_name, strain_name,death_cause, count(*) as Total
FROM ANIMALS a
JOIN GROUPS g ON a.group_id = g.id
JOIN STRAIN s ON a.strain_id = s.id
GROUP BY group_name, strain_name,death_cause

Answer 2

You can do the aggregation before joining the tables:

SELECT group_name, strain_name, death_cause, total
FROM   (
         SELECT   group_id,
                  strain_id,
                  death_cause,
                  COUNT(*) AS total
         FROM     animals
         GROUP BY group_id, strain_id, death_cause
       ) a
       INNER JOIN groups g ON ( g.group_id = a.group_id )
       INNER JOIN strain s ON ( s.strain_id = a.strain_id );