问题
I have a table of songs, some songs are album song, and some are singles... And I have a table of albums...
Example:
if the album ID is [null], it means the song is a single
Songs Table:
+--------+---------+-----------+----------------+---------+---------------+-------+--------+--------+------+-------+-------+----------+
| Row ID | Song ID | Album ID | Song Name | Band | Date Released | Genre | Lyrics | Lenght | Size | Plays | Likes | Dislikes |
+--------+---------+-----------+----------------+---------+---------------+-------+--------+--------+------+-------+-------+----------+
| 1 | Song-01 | Album-1 | Song-001 | Band-1 | 2010-12-15 | Rock | ... | 4:30 | 4 MB | 101 | 11 | 1 |
| 2 | Song-02 | Album-1 | Song-002 | Band-1 | 2010-12-15 | Rock | ... | 5:30 | 5 MB | 102 | 12 | 2 |
| 3 | Song-03 | Album-1 | Song-003 | Band-1 | 2010-12-15 | Rock | ... | 3:30 | 3 MB | 103 | 13 | 3 |
| 4 | Song-04 | [null] | Song-004 | Band-1 | 2010-12-16 | Rock | ... | 4:30 | 4 MB | 104 | 14 | 4 |
| 5 | Song-05 | Album-2 | Song-005 | Band-1 | 2010-12-17 | POP | ... | 3:30 | 3 MB | 105 | 15 | 5 |
| 6 | Song-06 | Album-2 | Song-006 | Band-1 | 2010-12-17 | RAP | ... | 5:30 | 5 MB | 106 | 16 | 6 |
| 7 | Song-07 | [null] | Song-007 | Band-2 | 2010-12-17 | Rock | ... | 3:30 | 3 MB | 107 | 17 | 7 |
| 8 | Song-08 | Album-3 | Song-008 | Band-2 | 2010-12-17 | Rock | ... | 4:30 | 4 MB | 108 | 18 | 8 |
| 9 | Song-09 | Album-3 | Song-009 | Band-2 | 2010-12-17 | POP | ... | 5:30 | 5 MB | 109 | 19 | 9 |
| 10 | Song-10 | Album-3 | Song-010 | Band-2 | 2010-12-17 | Punk | ... | 6:30 | 6 MB | 110 | 20 | 0 |
| 11 | Song-11 | Album-3 | Song-011 | Band-2 | 2010-12-17 | RAP | ... | 7:30 | 7 MB | 111 | 21 | 1 |
| 12 | Song-12 | [null] | Song-012 | Band-2 | 2010-12-18 | Rock | ... | 3:30 | 3 MB | 112 | 22 | 2 |
| 13 | Song-13 | [null] | Song-013 | Band-2 | 2010-12-18 | Rock | ... | 2:30 | 2 MB | 113 | 23 | 3 |
| 14 | Song-14 | [null] | Song-014 | Band-3 | 2010-12-18 | Rock | ... | 6:30 | 6 MB | 114 | 24 | 4 |
| 15 | Song-15 | [null] | Song-015 | Band-3 | 2010-12-19 | Rock | ... | 7:30 | 7 MB | 115 | 25 | 5 |
| 16 | Song-16 | [null] | Song-016 | Band-3 | 2010-12-19 | Rock | ... | 4:30 | 4 MB | 116 | 26 | 6 |
| 17 | Song-17 | [null] | Song-017 | Band-4 | 2010-12-19 | POP | ... | 3:30 | 3 MB | 117 | 27 | 7 |
| 18 | Song-18 | [null] | Song-018 | Band-4 | 2010-12-19 | POP | ... | 2:30 | 2 MB | 118 | 28 | 8 |
| 19 | Song-19 | [null] | Song-019 | Band-5 | 2010-12-20 | Rock | ... | 4:30 | 4 MB | 119 | 29 | 9 |
| 20 | Song-20 | [null] | Song-020 | Band-5 | 2010-12-20 | Rock | ... | 5:30 | 5 MB | 120 | 30 | 0 |
| 21 | Song-21 | [null] | Song-021 | Band-5 | 2010-12-20 | Rock | ... | 6:30 | 6 MB | 121 | 31 | 1 |
| 22 | Song-22 | Album-4 | Song-022 | Band-5 | 2010-12-21 | Rock | ... | 3:30 | 3 MB | 122 | 32 | 2 |
| 23 | Song-23 | Album-4 | Song-023 | Band-5 | 2010-12-21 | Rock | ... | 2:30 | 2 MB | 123 | 33 | 3 |
| 24 | Song-24 | Album-4 | Song-024 | Band-5 | 2010-12-21 | Rock | ... | 4:30 | 4 MB | 124 | 34 | 4 |
| 25 | Song-25 | [null] | Song-025 | Band-6 | 2010-12-22 | Rock | ... | 5:30 | 5 MB | 125 | 35 | 5 |
| 26 | Song-26 | [null] | Song-026 | Band-6 | 2010-12-22 | Rock | ... | 6:30 | 6 MB | 126 | 36 | 6 |
| 27 | Song-27 | Album-5 | Song-027 | Band-7 | 2010-12-22 | POP | ... | 4:30 | 4 MB | 127 | 37 | 7 |
| 28 | Song-28 | Album-5 | Song-028 | Band-7 | 2010-12-22 | PUNK | ... | 3:30 | 3 MB | 128 | 38 | 8 |
| 29 | Song-29 | [null] | Song-029 | Band-7 | 2010-12-23 | Rock | ... | 2:30 | 2 MB | 129 | 39 | 9 |
| 30 | Song-30 | Album-6 | Song-030 | Band-8 | 2010-12-25 | Rock | ... | 5:30 | 5 MB | 130 | 40 | 0 |
+--------+---------+-----------+----------------+---------+---------------+-------+--------+--------+------+-------+-------+----------+
Albums Table:
+--------+-----------+----------------+---------+---------------+-------------------+--------+-------+----------+
| Row ID | Album ID | Album Name | Band | Date Released | Genre | Lenght | Likes | Dislikes |
+--------+-----------+----------------+---------+---------------+-------------------+--------+-------+----------+
| 1 | Album-1 | Album One | Band-1 | 2010-12-15 | Rock | 13:30 | 101 | 31 |
| 2 | Album-2 | Album Two | Band-1 | 2010-12-17 | POP/RAP | 9:00 | 102 | 32 |
| 3 | Album-3 | Album Three | Band-2 | 2010-12-17 | Rock/Punk/POP/RAP | 24:00 | 103 | 33 |
| 4 | Album-4 | Album Four | Band-5 | 2010-12-21 | Rock | 10:30 | 104 | 34 |
| 5 | Album-5 | Album Five | Band-7 | 2010-12-22 | Punk/POP | 8:00 | 105 | 35 |
| 6 | Album-6 | Album Six | Band-8 | 2010-12-25 | Rock | 5:30 | 106 | 36 |
+--------+-----------+----------------+---------+---------------+-------------------+--------+-------+----------+
And If I want to take only the latest five albums and/or singles which means the result will be (ordered from latest to eldest):
by the column 'name' I mean 'Single name or Album name'
Page 1:
+-----------------+---------+-----------------+-------------------+----------+-----------+--------+--------+------+-------+----------+-------+
| Name | Band | Date Released | Genre | IsAlbum? | IsSingle? | Lyrics | Lenght | Size | Likes | Dislikes | Plays |
+-----------------+---------+-----------------+-------------------+----------+-----------+--------+--------+------+-------+----------+-------+
| Album Six | Band-8 | 2010-12-25 | Rock | YES | NO | - | 5:30 | -- | 106 | 36 | - |
| Song 29 | Band-7 | 2010-12-23 | Rock | NO | YES | ... | 2:30 | 2 MB | 39 | 9 | 129 |
| Album Five | Band-7 | 2010-12-22 | Punk/POP | YES | NO | - | 8:00 | -- | 105 | 35 | - |
| Song 26 | Band-6 | 2010-12-22 | Rock | NO | YES | ... | 6:30 | 6 MB | 36 | 6 | 126 |
| song 25 | Band-6 | 2010-12-22 | Rock | NO | YES | ... | 5:30 | 5 MB | 35 | 5 | 125 |
+-----------------+---------+-----------------+-------------------+----------+-----------+--------+--------+------+-------+----------+-------+
And If I want to take only the latest five after the latest five (the ones in the table above) albums and/or singles, the result will be ordered from latest to eldest):
Page 2:
+-----------------+---------+-----------------+-------------------+----------+-----------+--------+--------+------+-------+----------+-------+
| Name | Band | Date Released | Genre | IsAlbum? | IsSingle? | Lyrics | Lenght | Size | Likes | Dislikes | Plays |
+-----------------+---------+-----------------+-------------------+----------+-----------+--------+--------+------+-------+----------+-------+
| Album Four | Band-5 | 2010-12-21 | Rock | YES | NO | - | 10:30 | -- | 104 | 34 | - |
| Song 21 | Band-5 | 2010-12-20 | Rock | NO | YES | ... | 6:30 | 6 MB | 31 | 1 | 121 |
| Song 20 | Band-5 | 2010-12-20 | Rock | NO | YES | ... | 5:30 | 5 MB | 30 | 0 | 120 |
| Song 19 | Band-5 | 2010-12-20 | Rock | NO | YES | ... | 4:30 | 4 MB | 29 | 9 | 119 |
| song 18 | Band-4 | 2010-12-19 | POP | NO | YES | ... | 2:30 | 2 MB | 28 | 8 | 118 |
+-----------------+---------+-----------------+-------------------+----------+-----------+--------+--------+------+-------+----------+-------+
And the five before them will be:
Page 3:
+-----------------+---------+-----------------+-------------------+----------+-----------+--------+--------+------+-------+----------+-------+
| Name | Band | Date Released | Genre | IsAlbum? | IsSingle? | Lyrics | Lenght | Size | Likes | Dislikes | Plays |
+-----------------+---------+-----------------+-------------------+----------+-----------+--------+--------+------+-------+----------+-------+
| Song 17 | Band-4 | 2010-12-19 | POP | NO | YES | ... | 3:30 | 3 MB | 27 | 7 | 117 |
| Song 16 | Band-3 | 2010-12-19 | Rock | NO | YES | ... | 4:30 | 4 MB | 26 | 6 | 116 |
| Song 15 | Band-3 | 2010-12-19 | Rock | NO | YES | ... | 5:30 | 5 MB | 25 | 5 | 115 |
| Song 14 | Band-3 | 2010-12-18 | Rock | NO | YES | ... | 6:30 | 6 MB | 24 | 4 | 114 |
| song 13 | Band-2 | 2010-12-18 | Rock | NO | YES | ... | 2:30 | 2 MB | 23 | 3 | 113 |
+-----------------+---------+-----------------+-------------------+----------+-----------+--------+--------+------+-------+----------+-------+
And the five before:
Page 4:
+-----------------+---------+-----------------+-------------------+----------+-----------+--------+--------+------+-------+----------+-------+
| Name | Band | Date Released | Genre | IsAlbum? | IsSingle? | Lyrics | Lenght | Size | Likes | Dislikes | Plays |
+-----------------+---------+-----------------+-------------------+----------+-----------+--------+--------+------+-------+----------+-------+
| Song 12 | Band-2 | 2010-12-18 | Rock | NO | YES | ... | 3:30 | 3 MB | 22 | 2 | 112 |
| Album Three | Band-2 | 2010-12-17 | Rock/Punk/POP/RAP | YES | NO | - | 24:00 | -- | 103 | 33 | - |
| Song 7 | Band-2 | 2010-12-17 | Rock | NO | YES | ... | 3:30 | 3 MB | 17 | 7 | 107 |
| Album Two | Band-1 | 2010-12-17 | POP/RAP | YES | NO | - | 9:00 | -- | 102 | 32 | - |
| song 4 | Band-1 | 2010-12-16 | Rock | NO | YES | ... | 4:30 | 4 MB | 14 | 4 | 104 |
+-----------------+---------+-----------------+-------------------+----------+-----------+--------+--------+------+-------+----------+-------+
And in the last table (or page):
Page 5:
+-----------------+---------+-----------------+-------------------+----------+-----------+--------+--------+------+-------+----------+-------+
| Name | Band | Date Released | Genre | IsAlbum? | IsSingle? | Lyrics | Lenght | Size | Likes | Dislikes | Plays |
+-----------------+---------+-----------------+-------------------+----------+-----------+--------+--------+------+-------+----------+-------+
| Album One | Band-1 | 2010-12-15 | Rock | YES | NO | - | 13:00 | -- | 101 | 31 | - |
+-----------------+---------+-----------------+-------------------+----------+-----------+--------+--------+------+-------+----------+-------+
But, the problem is that when I do that the X and the Y in "LIMIT X , Y" won't be X=0,Y=5 or X=5,Y=5 or X=10,Y=5 and so on...
So, my question is: how can I do what I did above in PHP and SQL (MySQL) ?
Sorry for my english and, thanks in advance
回答1:
You're getting the LIMIT clauses wrong. it's OFFSET,QUANTITY. Your sample queries are fetching 5 records at a time, so the QUANTITY would be 5 at all times, and you'd increment the offset by 5 for each "page" of results.
Top 5 songs/albums: LIMIT 0,5
Top 6-10 songs/album: LIMIT 5,5
Top 11-15 songs/albums: LIMIT 10,5
etc...
回答2:
Here's my quick stab at your question, but I'm making some huge assumptions.
I believe that you want all albums and singles listed in the order of release and you want to show 5 per "page". Assuming that, this query should work. Long term I would turn this into a view.
SELECT "Name", "Date Released"
FROM (
SELECT "Album ID" as "Name", "Date Released" FROM Albums
UNION ALL
SELECT "Song Name" as "Name", "Date Released" FROM Songs WHERE "Album ID" IS NULL
) as AlbumsAndSingles
ORDER BY "Date Released" ASC
LIMIT X,5
Then, starting with 0, increment X in the query above by 5 on each page.
来源：https://stackoverflow.com/questions/5557730/need-help-with-php-and-mysql