Question

我进行了很多搜索，并尝试了许多查询，但未获得满意的答案。所以想问。

我正在从mysql表中查找最后的 5条记录，如果它们具有相同的值，否则就没有。

类似if col_n is having same value x from last 5 records then count otherwise not。但是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

请尝试以下操作：

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'

Mysql：如果具有相同的值，则最后五个记录

1 个答案: