选择一个不同的列,其他列可以是不同的。 - MySQL

时间:2011-01-06 10:37:31

标签: python sql mysql distinct distinct-values

好的我有一个135000行的临时表,我试图将这个临时表中的一些值插入到其他表中。

这是我正在使用的架构

tvtemptable

+-------------+-------------+------+-----+---------+-------+
| Field       | Type        | Null | Key | Default | Extra |
+-------------+-------------+------+-----+---------+-------+
| PROGTITLE   | text        | YES  |     | NULL    |       |
| SUBTITLE    | text        | YES  |     | NULL    |       |
| EPISODE     | text        | YES  |     | NULL    |       |
| YR          | year(4)     | YES  |     | NULL    |       |
| DIRECTOR    | text        | YES  |     | NULL    |       |
| PERFORMERS  | text        | YES  |     | NULL    |       |
| PREMIERE    | tinyint(1)  | YES  |     | NULL    |       |
| FILM        | tinyint(1)  | YES  |     | NULL    |       |
| RPEAT       | tinyint(1)  | YES  |     | NULL    |       |
| SUBTITLES   | tinyint(1)  | YES  |     | NULL    |       |
| WIDESCREEN  | tinyint(1)  | YES  |     | NULL    |       |
| NEWSERIES   | tinyint(1)  | YES  |     | NULL    |       |
| DEAFSIGNED  | tinyint(1)  | YES  |     | NULL    |       |
| BNW         | tinyint(1)  | YES  |     | NULL    |       |
| STARRATING  | tinyint(4)  | YES  |     | NULL    |       |
| CERTIFICATE | varchar(5)  | YES  |     | NULL    |       |
| GENRE       | varchar(50) | YES  |     | NULL    |       |
| DESCRIPTION | text        | YES  |     | NULL    |       |
| CHOICE      | tinyint(1)  | YES  |     | NULL    |       |
| PROGDATE    | date        | YES  |     | NULL    |       |
| STARTIME    | time        | YES  |     | NULL    |       |
| ENDTIME     | time        | YES  |     | NULL    |       |
| DURATION    | int(11)     | YES  |     | NULL    |       |
| CHANNELID   | int(11)     | NO   |     | NULL    |       |
+-------------+-------------+------+-----+---------+-------+

信道

+-------------+-------------+------+-----+---------+----------------+
| Field       | Type        | Null | Key | Default | Extra          |
+-------------+-------------+------+-----+---------+----------------+
| CHANNELID   | int(11)     | NO   | PRI | NULL    | auto_increment |
| CHANNELNAME | varchar(50) | YES  |     | NULL    |                |
+-------------+-------------+------+-----+---------+----------------+

类型

+-----------+-------------+------+-----+---------+----------------+
| Field     | Type        | Null | Key | Default | Extra          |
+-----------+-------------+------+-----+---------+----------------+
| GENREID   | int(11)     | NO   | PRI | NULL    | auto_increment |
| GENRENAME | varchar(50) | YES  |     | NULL    |                |
+-----------+-------------+------+-----+---------+----------------+

程序

+-------------+------------+------+-----+---------+----------------+
| Field       | Type       | Null | Key | Default | Extra          |
+-------------+------------+------+-----+---------+----------------+
| PROGRAMMEID | int(11)    | NO   | PRI | NULL    | auto_increment |
| GENREID     | int(11)    | NO   | MUL | NULL    |                |
| PROGTITLE   | text       | YES  |     | NULL    |                |
| YR          | year(4)    | YES  |     | NULL    |                |
| DIRECTOR    | text       | YES  |     | NULL    |                |
| PERFORMERS  | text       | YES  |     | NULL    |                |
| FILM        | tinyint(1) | YES  |     | NULL    |                |
| WIDESCREEN  | tinyint(1) | YES  |     | NULL    |                |
| BNW         | tinyint(1) | YES  |     | NULL    |                |
| CERTIFICATE | varchar(5) | YES  |     | NULL    |                |
| DESCRIPTION | text       | YES  |     | NULL    |                |
+-------------+------------+------+-----+---------+----------------+

插曲

+-------------+---------+------+-----+---------+----------------+
| Field       | Type    | Null | Key | Default | Extra          |
+-------------+---------+------+-----+---------+----------------+
| EPISODEID   | int(11) | NO   | PRI | NULL    | auto_increment |
| PROGRAMMEID | int(11) | NO   | MUL | NULL    |                |
| SUBTITLE    | text    | YES  |     | NULL    |                |
| EPISODE     | text    | YES  |     | NULL    |                |
| DIRECTOR    | text    | YES  |     | NULL    |                |
| PERFORMERS  | text    | YES  |     | NULL    |                |
| DESCRIPTION | text    | YES  |     | NULL    |                |
+-------------+---------+------+-----+---------+----------------+

channelprogramme

+--------------------+------------+------+-----+---------+----------------+
| Field              | Type       | Null | Key | Default | Extra          |
+--------------------+------------+------+-----+---------+----------------+
| CHANNELPROGRAMMEID | int(11)    | NO   | PRI | NULL    | auto_increment |
| CHANNELID          | int(11)    | NO   | MUL | NULL    |                |
| PROGRAMMEID        | int(11)    | NO   | MUL | NULL    |                |
| EPISODEID          | int(11)    | NO   | MUL | NULL    |                |
| RPEAT              | tinyint(1) | YES  |     | NULL    |                |
| NEWSERIES          | tinyint(1) | YES  |     | NULL    |                |
| PREMIERE           | tinyint(1) | YES  |     | NULL    |                |
| CHOICE             | tinyint(1) | YES  |     | NULL    |                |
| SUBTITLES          | tinyint(1) | YES  |     | NULL    |                |
| DEAFSIGNED         | tinyint(1) | YES  |     | NULL    |                |
| STARRATING         | tinyint(4) | YES  |     | NULL    |                |
| PROGDATE           | date       | YES  |     | NULL    |                |
| STARTTIME          | time       | YES  |     | NULL    |                |
| ENDTIME            | time       | YES  |     | NULL    |                |
| DURATION           | tinyint(4) | YES  |     | NULL    |                |
+--------------------+------------+------+-----+---------+----------------+

所以有一点背景,数据库是电视列表数据库,channelprogramme表包含每个频道上每个节目的所有条目,节目表包含每个节目的唯一条目,剧集包含每集的唯一条目有剧集的节目

我认为我的困惑是我想从临时表中选择不同的progtitles来填充程序表,但是我想要一些其他的信息。

例如,如果我做了

select distinct(progtitle) from tvtemptable;

它只返回progtitle列的值,而我实际想要的是progtitle加上其他一些东西。

所以,如果我尝试选择更多这样的信息

mysql> select distinct progtitle, yr, director, film from tvtemptable
limit 30;
+-----------------------------------+------+---------------------+------+
| progtitle                         | yr   | director            | film |
+-----------------------------------+------+---------------------+------+
| Teleshopping                      | 2000 |                     |    0 |
| Cinemania                         | 2000 |                     |    0 |
| Whose Line Is It Anyway?          | 2000 |                     |    0 |
| Just Desserts                     | 2004 | Kevin Connor        |    1 |
| Law & Order                       | 2000 | Matthew Penn        |    0 |
| Jane Doe: Yes, I Remember it Well | 2006 | Armand Mastroianni  |    0 |
| CSI: NY                           | 2000 | David Jackson       |    0 |
| CSI: Crime Scene Investigation    | 2000 | Kenneth Fink        |    0 |
| NCIS                              | 2000 | Colin Bucksey       |    0 |
| CSI: Miami                        | 2000 |                     |    0 |
| Enter the Dragon                  | 1973 | Robert Clouse       |    1 |
| Close                             | 2000 |                     |    0 |
| My Son Is Innocent                | 1996 | Larry Elikann       |    1 |
| Law & Order                       | 2000 | Christopher Misiano |    0 |
| Murder 101                        | 2006 | Christian I Nyby II |    1 |
| CSI: NY                           | 2000 | Christine Moore     |    0 |
| CSI: Crime Scene Investigation    | 2000 | Bill Eagles         |    0 |
| Rush Hour                         | 1998 | Brett Ratner        |    1 |
| Dark Blue                         | 2000 | Jeffrey Hunt        |    0 |
| CSI: Crime Scene Investigation    | 2000 | Richard J Lewis     |    0 |
| Ordinary Miracles                 | 2005 | Michael Switzer     |    1 |
| Law & Order                       | 2000 | Jace Alexander      |    0 |
| Wounded Heart                     | 1995 | Vic Sarin           |    1 |
| CSI: NY                           | 2000 | Jonathan Glassner   |    0 |
| Dark Blue                         | 2000 | Nathan Hope         |    0 |
| Blade: The Series                 | 2000 | Michael Robison     |    0 |
| K-Ville                           | 2000 | Kevin Dowling       |    0 |
| Law & Order                       | 2000 | Jim Ellis           |    0 |
| Reasons of the Heart              | 1996 | Rick Jacobson       |    1 |
| CSI: NY                           | 2000 | Anthony Hemingway   |    0 |
+-----------------------------------+------+---------------------+------+

progtitle列中会有一些重复项。每个新导演都不会重复这些节目,某些节目上面有不同的导演,因为这些节目有剧集。

现在我已经设法让选择正常工作如果我只需要一个额外的列例如

select distinct
    t1.progtitle,
   (select
        t2.director
    from
        tvtemptable t2
    where 
        t1.progtitle = t2.progtitle
    limit 1) as "Director"
from
    tvtemptable t1 limit 10;

+-----------------------------------+--------------------+
| progtitle                         | Director           |
+-----------------------------------+--------------------+
| Teleshopping                      |                    |
| Cinemania                         |                    |
| Whose Line Is It Anyway?          |                    |
| Just Desserts                     | Kevin Connor       |
| Law & Order                       | Matthew Penn       |
| Jane Doe: Yes, I Remember it Well | Armand Mastroianni |
| CSI: NY                           | David Jackson      |
| CSI: Crime Scene Investigation    | Kenneth Fink       |
| NCIS                              | Colin Bucksey      |
| CSI: Miami                        |                    |
+-----------------------------------+--------------------+

显然这会变得混乱如果我想选择多个额外的列

那么最好的方法是什么?

这是我用于从临时表中填充程序表的插入命令,目前它与我在上面给出的选择示例中的重复项有相同的问题。

INSERT INTO PROGRAMME (
    PROGTITLE, GENREID, YR, DIRECTOR,
    PERFORMERS, FILM, WIDESCREEN, BNW,
    CERTIFICATE, DESCRIPTION)
SELECT DISTINCT
    T.PROGTITLE, G.GENREID, T.YR, T.DIRECTOR,
    T.PERFORMERS, T.FILM, T.WIDESCREEN, T.BNW,
    T.CERTIFICATE, T.DESCRIPTION
FROM
    TVTEMPTABLE T
    INNER JOIN GENRE G ON G.GENRENAME=T.GENRE
    LEFT JOIN PROGRAMME P ON P.PROGTITLE=T.PROGTITLE
WHERE
    P.PROGTITLE IS NULL

5 个答案:

答案 0 :(得分:0)

这没有意义。一行如何部分区分并且部分不同?将所选结果视为一个表 - 如果PROGTITLE有一个值,其余列有多个值,您将如何表示数据?

答案 1 :(得分:0)

这不能回答你的问题,但可能会回答那些在谷歌上搜索的人:

在Postgresql中,您可以使用SELECT DISTINCT ON执行此操作,例如:

SELECT DISTINCT ON (p.progtitle) p.* FROM progtitle p;

我不知道MySQL的任何等价物。

答案 2 :(得分:0)

Insert into xx (a,b) 
Select a.ab, b.bb from (
Select distinct ab from a) a, (select distinct bb from b) b

答案 3 :(得分:0)

我是否正确地认为您的TVTEMPTABLE是来自某个地方的表格连接的结果?

如果是这种情况,如果您首先将该临时表拆分为多个与目标表格格式相同的临时表,我认为您的整体工作会更轻松。

例如(我不知道您的数据,所以我猜):

-- All genres (matches your existing genres table)
create table genres_temp as
   select distinct genre
     from tvtemptable;

-- All programmes (matches your existing programme table)
create table programmes_temp as
   select distinct all_the_programme_columns
     from tvtemptable;

-- Contains the many-to-many relationship between genres and programmes
create table programme_genre_temp as 
   select distinct genre, progtitle
     from tvtemptable;

上面没有回答你的问题,但它可能会给你一些消除问题的想法,似乎是每个某事重复了程序信息。你需要找出它是什么。

<强>更新 那么每个导演都会重复一次每个节目? 然后我的上述方法更有意义:首先提取实体和关系。

更新2 嗯,当导演与剧集有关时,你强迫导演进入节目吗?这似乎是一个建模错误。无论如何,如果您不关心自己选择的导演,可以在progtitle上进行分组,并在所有其他专栏周围使用MAX()。这将为您提供不同的progtitles和其余列的值之一。

SELECT T.PROGTITLE, max(G.GENREID), max(T.YR), max(T.DIRECTOR), etc
  FROM TVTEMPTABLE T
 INNER JOIN GENRE G ON G.GENRENAME=T.GENRE
       LEFT JOIN PROGRAMME P ON P.PROGTITLE=T.PROGTITLE
 WHERE P.PROGTITLE IS NULL
 group by T.PROGTITLE;

答案 4 :(得分:0)

我正在读你想要的是一个不同程序的列表,但在上下文的其他列中有一些相关数据?你可以用行号来做到这一点。

select * from
 (select *,
         row_number() over (partition by progtitle order by year desc) N
    from tvtempta) t
where t.N = 1

更好的是,您可以使用order by子句指定选择所需行的最新,第一或其他首选方式。这是T-SQL语法,我认为相同的语法应该在Oracle中起作用(如果不是,它在Oracle中肯定是可行的)。不幸的是,我不知道你是否可以在MySQL中做到这一点。