Difference between revisions of "SQLZOO:SELECT basics"

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<div class="ref_section">
<table class='db_ref'>
<tr><td>Afghanistan</td><td>Asia</td><td class="r">652230</td><td class="r">25500100</td><td class="r">20343000000</td></tr>
<tr><td>Albania</td><td>Europe</td><td class="r">28748 </td><td class="r">2831741 </td><td class="r">12960000000 </td></tr>
<tr><td>Algeria</td><td>Africa</td><td class="r">2381741 </td><td class="r">37100000 </td><td class="r">188681000000 </td></tr>
<tr><td>Andorra</td><td>Europe</td><td class="r">468</td><td class="r">78115 </td><td class="r">3712000000 </td></tr><tr>
<td>Angola</td><td>Africa</td><td class="r">1246700 </td><td class="r">20609294 </td><td class="r">100990000000 </td></tr>
<td colspan='5'>....</td>
http://riverbendsudan.com/ ,  , http://seesbeauty.me/ ,  , http://onlinetabsonline.com/ ,  , http://onlinepillsonline.com/ ,  ,
<div class='qu'>
Checking a list The word <b>IN</b> allows us to check if an item is in a list.
The example shows the name and population for the countries 'Ireland', 'Iceland' and 'Denmark'
<div class='imper'>Show the '''name''' and the '''population''' for 'Denmark', 'Finland', 'Norway', 'Sweden'
<source lang='sql' class='def'>
SELECT name, population FROM world
  WHERE name IN ('Ireland', 'Iceland',
<source lang='sql' class='ans'>
SELECT name, population FROM world
  WHERE name IN ('Denmark', 'Finland',
                'Norway', 'Sweden')</source>
==Starts with G==
<div class='qu'>
What are the countries beginning with G?
'''The word''' <code>LIKE</code> '''permits pattern matching''' - % '''is the wildcard'''.
The examples shows countries beginning with D
<div class='imper'>Show each country that begins with G</div>
<source lang='sql' class='def'>
SELECT name FROM world
  WHERE name LIKE 'D%'
<source lang='sql' class='ans'>
SELECT name FROM world
  WHERE name LIKE 'G%'
==Just the right size==
<div class='qu'>
Which countries are not too small and not too big? Show the country and the area for countries with an area between 207600 and 244820.
<code>BETWEEN</code> allows range checking - note that it is inclusive.
<div class='imper'>'''Show the area in 1000 square km. Show''' ''area''/1000 '''instead of''' ''area''</div>
<source lang='sql' class='def'>
SELECT name, area FROM world
  WHERE area BETWEEN 207600 AND 244820...
<source lang='sql' class='ans'>
SELECT name, area/1000 FROM world
  WHERE area BETWEEN 207600 AND 244820
<div class="lsclear">Clear your results</div>
<p><div class="quizlink">[[SELECT Quiz]]</div></p>
<p>You are ready for tutorial one:[[SELECT_from_WORLD_Tutorial |SELECT statements with WHERE.]]</p>

Latest revision as of 11:45, 25 May 2016

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