php - mysql : last five records if having same value

Question

我进行了很多搜索并尝试了很多查询，但没有得到满意的答案。所以想问一下。

如果具有相同的值，我正在从 mysql 表中查找最后 5 条记录，否则不会。

类似于如果 col_n 在最后 5 条记录中具有相同的值 x，则计数，否则不计数。但我不知道如何为此编写查询？

SELECT count(col_n) 
from track if(last five col_n = 'ok') 
WHERE col_a = 'value1' AND col_b = 'value2' 

enter mysql table records

Answer 1

请尝试这个:

SELECT  p.*
FROM
    ( SELECT * 
      FROM   demo  ORDER by id DESC
      LIMIT 5
    ) AS p
  JOIN
    ( SELECT COUNT(*) AS cnt
      FROM   
        ( SELECT 1 
          FROM   demo
          LIMIT 5
        ) AS tmp
    ) AS c
    ON c.cnt = 5 WHERE p.name='x'