Question

我正在使用MYSQL，我正在寻找一种方法来只选择一行，前一行和下一行有一个名为fav_num的字段，值为'3'

例如，我有6行和2个字段。字段是ID和fav_number。

 ID| fav_num
 1 | 3
 2 | 2
 3 | 3
 4 | 7
 5 | 2
 6 | 9

我想找到一种方法从表中返回ID，其中上一行和下一行的fav_num为3。然后，此查询将返回ID 2。

如果我的问题听起来令人困惑，我道歉。

Answer 1

我认为这可行..

SELECT id
  FROM tab t
 WHERE t.id BETWEEN
       (SELECT MAX(id) FROM tab tp WHERE tp.id < t.id AND tp.fav_num = 3)
   AND (SELECT MIN(id) FROM tab tn WHERE tn.id > t.id AND tn.fav_num = 3)

Answer 2

请试试这个：

SELECT a.id FROM test1 a WHERE 
3=(SELECT fav_num FROM test1 WHERE id = (SELECT MAX(id) FROM test1 WHERE id <a.id)) AND 
3=(SELECT fav_num FROM test1 WHERE id = (SELECT MIN(id) FROM test1 WHERE id >a.id)) ;


SELECT a.id FROM test1 a WHERE 
EXISTS (SELECT 1 FROM test1 WHERE id = (SELECT MAX(id) FROM test1 WHERE     id <a.id) AND fav_num=3) AND 
EXISTS (SELECT 1 FROM test1 WHERE id = (SELECT MIN(id) FROM test1 WHERE  id >a.id)  AND fav_num=3) ;

我不确定这种表现。

Answer 3

SELECT ID FROM tbl WHERE fav_num BETWEEN '1' AND '3';

Answer 4

http://sqlfiddle.com/#!9/2b6fb0/12

SELECT t1.*
FROM t1
INNER JOIN (SELECT 
    @d1:=0+@d2 d1,
    @d2:=0+@d3 d2,
    @d3:=fav_num d3,
    @previd:=@id prevID,
    @id:=id 
FROM (
  SELECT *
  FROM t1 
  ORDER BY id) t
) filter
ON filter.d1 = 3
   AND filter.d3 = 3
   AND t1.id = filter.prevID
;

我可以选择具有上一行和下一行条件的行吗？

4 个答案: