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For 2021 - online Python 3 training - see ((here)).

Our plans were to retire in summer 2020 and see the world, but Coronavirus has lead us into a lot of lockdown programming in Python 3 and PHP 7.
We can now offer tailored online training - small groups, real tutors - works really well for groups of 4 to 14 delegates. Anywhere in the world; course language English.

Please ask about private 'maintenance' training for Python 2, Tcl, Perl, PHP, Lua, etc.
An occasional chance, and reducing data to manageable levels

If there's a 1 in 5 (20%) chance of it being a dry day at the moment, a 20% chance of it not being freezing cold, and a 20% chance of me having a day that I'm not training or otherwise involved, then it follows (since the conditions aren't related) that there's just a 1 in 125 or less that 1% chance of all three co-inciding. A.k.a. "fat chance".

Which is why you would have found me and Lisa, yesterday, re-roofing the conservatory / store room in which newsletters, envelopes, cables and 101 other business supplies are kept. The plastic sheeting on the roof of this '60s addition to our place was - to put it mildly - life expired and there was a real danger of some of the things kept in there getting damaged so we simply couldn't wait for a co-incidence of three 1-in-5s. "Between showers" is, I think, the best way to describe what we did; it was a darned sight dryer that the last few days which have lead, once again, to the formation of Lake Melksham.

Interestingly, SQL SELECT commands also use this principle of "a proportion of a proportion is a tiny bit of data" to reduce the amount of information supplied back to the using application by a database. In a select command, you specify which columns you want, and you also specify which rows you want. Which leads to a rapid data reduction. For example, if you have a 10 Mbyte database table and you select just 4 columns out of 20, and then just 100 rows out of 10000, your result set will be just 20k.

(written 2005-12-04, updated 2006-06-09)

 
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)
  [279] Getting a list of unique values from a MySQL column - (2005-04-14)
  [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)
  [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)

G100 - Well House Consultants - Introduction to Melksham
  [269] Free parking for short errands in Melksham - (2005-04-05)
  [291] Why are we no. 404 - (2005-04-25)
  [322] More maps - (2005-05-23)
  [676] Melksham, Wiltshire - (2006-04-08)
  [847] Image maps for navigation - a straightforward example - (2006-08-28)
  [866] A lazy programmer is a good programmer - (2006-09-15)
  [1341] Moving to Melksham? Househunting map. - (2007-09-09)
  [1725] A future vision for Melksham - (2008-07-27)
  [2329] Great to be in Melksham - (2009-08-08)
  [2350] Ten years in Melksham - looking forward to ten more. - (2009-08-11)
  [2704] A walk within without - Melksham Without - (2010-04-02)
  [3232] Around and about Melksham in more pictures - (2011-04-05)
  [3344] Repost - some useful pages on our site - (2011-07-04)
  [3696] Melksham government and business organisations - (2012-04-14)
  [3932] River nearly bursting its banks in Melksham - (2012-11-23)


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This is a page archived from The Horse's Mouth at http://www.wellho.net/horse/ - the diary and writings of Graham Ellis. Every attempt was made to provide current information at the time the page was written, but things do move forward in our business - new software releases, price changes, new techniques. Please check back via our main site for current courses, prices, versions, etc - any mention of a price in "The Horse's Mouth" cannot be taken as an offer to supply at that price.

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