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[Acronym] for __S__tructured __Q__uery __L__anguage.  Some database professionals think the S should stand for 'stupid'.

SQL is a set-centric ProgrammingLanguage in which statements are excuted over a [Schema] of relations (tables), and return a set of results.

!!Syntax & examples

In this example, imagine we have a table called 'users' which has links an 'id', a 'name' and an 'accesslevel'.

__Retrieving data:__

    <tt>SELECT ''cols'' FROM ''tables'' WHERE ''condition''</tt>%%%eg to find the access level of user number 154: <tt>SELECT accesslevel FROM users WHERE id = 154;</tt>

__Inserting data:__

    <tt>INSERT INTO ''table'' (''columns'') VALUES (''values'')</tt>%%%eg to add a new user: <tt>INSERT INTO users (name, accesslevel) VALUES ('Craig', 10);</tt> - the next available ID number is automatically assigned.

__Updating data:__

    <tt>UPDATE ''table'' SET ''column''=''value'' WHERE ''condition''</tt>%%%eg to set an accesslevel of 15 to everyone whos name starts with a C: <tt>UPDATE users SET accesslevel=15 WHERE name LIKE 'C%';</tt>

__Removing data:__

    <tt>DELETE FROM ''table'' WHERE ''condition''</tt>%%%eg Remove user with ID number 30: <tt>DELETE FROM users WHERE id = 30;</tt>

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CategoryProgrammingLanguages, CategorySpecialPurposeProgrammingLanguages

23 pages link to SQL:

Version 6, saved on Monday, May 15, 2006 4:16:21 pm by CraigBox

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