Combinations - Revision history

Connor at 15:00, 2 August 2012

2012-08-02T15:00:08Z

2012-08-02T10:39:30Z

2012-08-02T10:15:48Z

2012-08-02T10:10:05Z

2012-08-02T09:57:12Z

2012-07-30T13:35:55Z

@@ Line 1: / Line 1: @@
-A <code>JOIN</code> with no join conditions results in every row in one table being connected to every row in another table, forming all possible row combinations.
+<p>A <code>JOIN</code> with no join conditions results in every row in one table being connected to every row in another table, forming all possible row combinations.</p>
-Often this is done by mistake, but it can be useful. In this example we use this as an advantage to show the goals
+<p>Often this is done by mistake, but it can be useful. In this example we use this as an advantage to show the goals
-made for all games.
+made for all games.</p>
 <div class='ht'>
 <div class=params>schema:scott</div>

@@ Line 23: / Line 23: @@
 INSERT INTO tscores VALUES ('Wildcats', 'Toads', 0, 0);
 INSERT INTO tscores VALUES ('Lions', 'Tigers', 0, 0);
 </source>
 <div>

@@ Line 1: / Line 1: @@
-Generate combinations
+A <code>JOIN</code> with no join conditions results in every row in one table being connected to every row in another table, forming all possible row combinations.
 <div class='ht'>
 <div class=params>schema:scott</div>
@@ Line 18: / Line 20: @@
 INSERT INTO tscores VALUES ('Toads', 'Tigers', 3, 5);
 INSERT INTO tscores VALUES ('Wildcats', 'Tigers', 0, 0);
 </source>
 <div>
-<p>In this example we are attempting to obtain the scores for all games
+<p>To get all possible values a <code>CROSS JOIN</code> is used.</p>
-played.</p>
+<p>Conditions as well as a <code>LEFT JOIN</code> are then used to filter the query and make it more accurate.</p>
 <p>To get all possible values a <code>CROSS JOIN</code> is used</p>
-<p>Conditions as well as a left join are then used to filter the query and make it more accurate.</p>
 </div>
 <source lang='sql' class='def'>SELECT home.teamname Home, away.teamname Away,

@@ Line 22: / Line 22: @@
 <p>In this example we are attempting to obtain the scores for all games
 played.</p>
-To get all possible values a <code>CROSS JOIN</code> is used and then conditions as well as
+<p>To get all possible values a <code>CROSS JOIN</code> is used</p>
-a left join are then used to filter the query and make it more accurate.
+<p>Conditions as well as a left join are then used to filter the query and make it more accurate.</p>
 </div>
 <source lang='sql' class='def'>SELECT home.teamname Home, away.teamname Away,

@@ Line 34: / Line 34: @@
 <p>Conditions as well as a <code>LEFT JOIN</code> are then used to filter the query and make it more accurate.</p>
 </div>
-<source lang='sql' class='def'>SELECT home.teamname Home, away.teamname Away,
+<source lang='sql' class='def'>
 tscores.homescore, tscores.awayscore
-FROM teams home CROSS JOIN teams away LEFT JOIN tscores ON
+  FROM teams home CROSS JOIN teams away LEFT JOIN tscores ON
    (home.teamname = tscores.hometeam
     AND tscores.awayteam = away.teamname)
-WHERE home.teamname != away.teamname</source>
+  WHERE home.teamname != away.teamname</source>
 <div class="ecomm e-mysql" style="display: none"></div>
 </div>
 {{Hacks Ref}}