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For 2023 (and 2024 ...) - we are now fully retired from IT training.
We have made many, many friends over 25 years of teaching about Python, Tcl, Perl, PHP, Lua, Java, C and C++ - and MySQL, Linux and Solaris/SunOS too. Our training notes are now very much out of date, but due to upward compatability most of our examples remain operational and even relevant ad you are welcome to make us if them "as seen" and at your own risk.

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I am also active in many other area and still look after a lot of web sites - you can find an index ((here))
Getting a list of unique values from a MySQL column

Would you like to get a list of all the different values in a column? Use the DISTINCT keyword. Here's an example:


mysql> select * from train;
+-------+--------+-------------+-----+
| time | length | destination | tid |
+-------+--------+-------------+-----+
| 07:05 | 1 | Salisbury | 1 |
| 08:18 | 2 | Swindon | 2 |
| 09:05 | 2 | Southampton | 3 |
| 05:45 | 1 | Swindon | 4 |
| 10:35 | 12 | Plymouth | 10 |
| 13:49 | 2 | Swindon | 6 |
| 14:20 | 2 | Salisbury | 7 |
| 17:07 | 1 | Swindon | 8 |
| 18:18 | 1 | Salisbury | 9 |
| 13:00 | 6 | Windsor | 11 |
+-------+--------+-------------+-----+
10 rows in set (0.04 sec)

mysql> select distinct destination from train;
+-------------+
| destination |
+-------------+
| Salisbury |
| Swindon |
| Southampton |
| Plymouth |
| Windsor |
+-------------+
5 rows in set (0.08 sec)

mysql>


See More on SQL module.


(written 2005-04-14, updated 2006-06-05)

 
Associated topics are indexed as below, or enter http://melksh.am/nnnn for individual articles
S157 - More MySQL commands
  [158] MySQL - LEFT JOIN and RIGHT JOIN, INNER JOIN and OUTER JOIN - (2004-12-20)
  [159] MySQL - Optimising Selects - (2004-12-21)
  [449] Matching in MySQL - (2005-09-24)
  [494] MySQL - a score of things to remember - (2005-11-12)
  [502] SELECT in MySQL - choosing the rows you want - (2005-11-22)
  [513] MySQL - JOIN or WHERE to link tables correctly? - (2005-12-01)
  [515] MySQL - an FAQ - (2005-12-03)
  [517] An occasional chance, and reducing data to manageable levels - (2005-12-04)
  [567] Combining similar rows from a MySQL database select - (2006-01-17)
  [572] Giving the researcher power over database analysis - (2006-01-22)
  [581] Saving a MySQL query results to your local disc for Excel - (2006-01-29)
  [591] Key facts - SQL and MySQL - (2006-02-04)
  [673] Helicopter views and tartans - (2006-04-06)
  [1213] MySQL - the order of clauses and the order of actions - (2007-06-01)
  [1235] Outputting numbers as words - MySQL with Perl or PHP - (2007-06-17)
  [1331] MySQL joins revisited - (2007-09-03)
  [1574] Joining MySQL tables revisited - finding nonmatching records, etc - (2008-03-15)
  [1735] Finding words and work boundaries (MySQL, Perl, PHP) - (2008-08-03)
  [1904] Ruby, Perl, Linux, MySQL - some training notes - (2008-11-23)
  [2110] MySQL - looking for records in one table that do NOT correspond to records in another table - (2009-03-31)
  [2259] Grouping rows for a summary report - MySQL and PHP - (2009-06-27)
  [2448] MySQL - efficiency and other topics - (2009-10-10)
  [2643] Relating tables with joins in MySQL - (2010-02-21)
  [2644] Counting rows in joined MySQL tables - (2010-02-22)
  [2645] Optimising and caching your MySQL enquiries - (2010-02-22)
  [2647] Removing duplicates from a MySQL table - (2010-02-22)
  [3061] Databases - why data is split into separate tables, and how to join them - (2010-11-20)
  [3270] SQL - Data v Metadata, and the various stages of data selection - (2011-04-29)
  [4481] Extracting data from backups to restore selected rows from MySQL tables - (2015-05-01)


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Comment: "Havent seen your site crop up in sql searches for years. I ..."
Visitor Ranking 4.0 (5=excellent, 1=poor)

Comment by Colin (published 2010-10-08) Suggested link.
Havent seen your site crop up in sql searches for years. I this page found searching for a solution to a slightly different problem:
I need a list of unique values AND an id. Any id will do. First or last.
So how from your table: How to return the distinct destination along with a `tid` Pick a tid, any tid?

stackoverflow has a similar prob. I give link. My col I want unique has some heavy calcs so am trying to avoid multi selects and joins as far as poss. [#3783]

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