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  • Committer: Brian Aker
  • Date: 2011-02-22 06:12:02 UTC
  • mfrom: (2190.1.6 drizzle-build)
  • Revision ID: brian@tangent.org-20110222061202-k03czxykqy4x9hjs
List update, header fixes, multiple symbols, and David deletes some code.

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docs/functions/count.rst
 
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COUNT
 
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-----
 
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Take the following "Nodes" table, where 'nodes' are user-contributed content:
 
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+--------+-------------------+------------+----------------+-------------------+
 
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|NodeID  |ContributionDate   |NodeSize    |NodePopularity  |UserName           |
 
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+--------+-------------------+------------+----------------+-------------------+
 
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|1       |12/22/2010         |160         |2               |Smith              |
 
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+--------+-------------------+------------+----------------+-------------------+
 
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|2       |08/10/2010         |190         |2               |Johnson            |
 
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+--------+-------------------+------------+----------------+-------------------+
 
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|3       |07/13/2010         |500         |5               |Baldwin            |
 
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+--------+-------------------+------------+----------------+-------------------+
 
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|4       |07/15/2010         |420         |2               |Smith              |
 
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+--------+-------------------+------------+----------------+-------------------+
 
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|5       |12/22/2010         |1000        |4               |Wood               |
 
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+--------+-------------------+------------+----------------+-------------------+
 
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|6       |10/2/2010          |820         |4               |Smith              |
 
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+--------+-------------------+------------+----------------+-------------------+
 
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The SQL COUNT function returns the number of rows in a table satisfying the criteria specified in the WHERE clause. If we want to count how many orders has made a customer with CustomerName of Smith, we will use the following SQL COUNT expression:
 
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.. code-block:: mysql
 
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        SELECT COUNT * FROM Nodes
 
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        WHERE UserName = "Smith";
 
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In the above statement, the COUNT keyword returns the number 3, because the user Smith has 3 total nodes.
 
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If you don’t specify a WHERE clause when using the COUNT keyword, your statement will simply return the total number of rows in the table, which would be 6 in this example:
 
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.. code-block:: mysql
 
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        SELECT COUNT * FROM Nodes;