SELECT IT1.date1, ITM.date2, IT1.table_name, IT2.count_table - ITM.count_table AS diff
FROM input_table IT1
cross JOIN (
    SELECT *
    FROM input_table IT2
    WHERE IT1.DATE < it2.DATE and IT1.table_name = IT2.table_name)
) ITM

如果有多个日期和实体，那么您可以使用下面的代码。我刚用mariadb写的。可以通过更改临时表语法在任何数据库中使用。

CREATE TABLE test(dates date, table_name varchar(10), count_table INT);
 INSERT INTO test(dates, table_name, count_table) 
 VALUES('2018-07-19','A', 50),
 ('2018-07-19', 'B', 40),
 ('2018-07-18', 'A', 25),
 ('2018-07-18', 'B', 30),
 ('2018-07-17', 'A', 10),
 ('2018-07-17', 'B', 5);

 CREATE TEMPORARY TABLE test2(dates date, table_name varchar(10), count_table INT, Ranks INT);

INSERT INTO test2
select *, ROW_NUMBER() OVER(partition BY table_name order by dates) as Ranks
from test;

select t1.dates as date1, t2.dates as date2, t1.table_name, t2.count_table - t1.count_table
from test2 t1
INNER JOIN test2 t2 ON t1.table_name = t2.table_name and t1.ranks = t2.ranks - 1
ORDER BY table_name, t1.dates

在一个查询中使用同一个表两次，并给它一个别名。

SELECT a.date AS date1, b.date AS date2, a.table_name AS table_name, b.count_table - a.count_table AS diff
   FROM yourTable a, yourTable b
   WHERE a.date1 < b.date2
   GROUP BY date1, date2, table_name