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  • Committer: Lee Bieber
  • Date: 2011-01-25 20:11:28 UTC
  • mfrom: (2114.1.5 build)
  • Revision ID: kalebral@gmail.com-20110125201128-zhhu9kgcmmv2p11y
Merge Lee - 706121: innodb.innodb_bug53756.test relies on functionality not provided by test-run.pl
Merge Monty - Added inter-plugin dependencies for controlling plugin load order
Merge Marisa - 684803: Need to update Drizzledump documentation with migration conversions / caveats
Merge Marisa - 686641: Need to document removal of multi-table update/delete from Drizzle

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docs/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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        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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        SELECT COUNT * FROM Nodes;