Question

我不敢肯定,我是否必须拿出一张纸板或一些子座来取得预期结果,但表一是:

asset_id    id       title           title_type
34           1       episode 1       5
34           2       TNS             4
34           3       WXPR            3
35           4       episode 57      5
35           5       BLSH            4
35           6       WXRE            3
36           7       episode 56      5
36           8       BLSH            4
36           9       WXRE            3

但这正是我所希望的。标题: 4 = BLSH。因此:

asset id       title_type 5     title_type 4    title_type 3 
35             episode 56       BLSH            WXRE
36             episode 57       BLSH            WXRE

Answer 1

真正的课程设置是改变贵国的数据库结构......

然而,您可以利用JOIN获得所需数据。举例来说,没有分选:

SELECT 
  o.asset_id, 
  /* select the data from the self-joins */
  `5`.title AS title_type_5,
  `4`.title AS title_type_4,
  `3`.title AS title_type_3
FROM 
  foo o
/* use self-joins to combine data of multiple rows in a single row */
LEFT JOIN foo `3` ON `3`.title_type = 3 AND `3`.asset_id = o.asset_id
LEFT JOIN foo `4` ON `4`.title_type = 4 AND `4`.asset_id = o.asset_id
LEFT JOIN foo `5` ON `5`.title_type = 5 AND `5`.asset_id = o.asset_id
WHERE 
  o.title_type = "4" 
  AND o.title = "BLSH"

rel=“nofollow>> Try my example on Proffiddle

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