MySQL 8.0

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CREATE TABLE `animals` (
  `timestamp` datetime NOT NULL,
  `animal` tinytext NOT NULL,
  `comment` text NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

INSERT INTO `animals` (`timestamp`, `animal`, `comment`) VALUES
('2019-06-03 09:09:00', 'dog', 'good'),
('2019-06-03 12:00:00', 'cat', ''),
('2019-06-03 19:00:00', 'cat', ''),
('2019-07-04 09:00:00', 'cat', ''),
('2019-07-04 12:00:00', 'cat', 'feisty'),
('2019-07-04 18:51:00', 'dog', ''),
('2019-08-05 09:00:00', 'cat', ''),
('2019-08-05 12:00:00', 'cat', ''),
('2019-08-05 19:00:00', 'cat', ''),
('2019-09-06 09:00:00', 'cat', ' evil'),
('2019-09-06 12:00:00', 'cat', ''),
('2019-09-06 19:00:00', 'cat', '')
select 
    date_format(`timestamp`, '%Y-%m') `month`,
    sum(`animal` = 'dog') dog,
    sum(`animal` = 'cat') cat
from `animals` 
group by `month`
order by `month`


month
dog
cat


2019-06
1
2

2019-07
1
2

2019-08
0
3

2019-09
0
3


SET @sql = NULL;
SELECT
  GROUP_CONCAT(DISTINCT
    CONCAT(
      'Sum(`animal` =  ''',
      col,
      ''')  as `', 
      col, '`')
  ) INTO @sql
FROM
(
  select animal col
  from animals
)d;
SELECT @sql;


@sql


Sum(`animal` =  'cat')  as `cat`,Sum(`animal` =  'dog')  as `dog`


SET @sql = CONCAT('SELECT date_format(`timestamp`, "%Y-%m") `month`, ', @sql, ' 
                  from `animals` 
                  group by `month`
                  order by `month`');
SELECT @sql;


@sql


SELECT date_format(`timestamp`, "%Y-%m") `month`, Sum(`animal` =  'cat')  as `cat`,Sum(`animal` =  'dog')  as `dog` 
                  from `animals` 
                  group by `month`
                  order by `month`


PREPARE stmt FROM @sql;
EXECUTE stmt;
DEALLOCATE PREPARE stmt;


month
cat
dog


2019-06
2
1

2019-07
2
1

2019-08
3
0

2019-09
3
0