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Executing Queries
=================
Queries retrieve data from a database based on specific criteria. They
are performed with the declarative SELECT statement, which has no
persistent effects on the database. SELECT simply retrieves data from
one or more tables, or expressions.
A query includes a list of columns to be included in a result set; an example of this would be: ::
SELECT * FROM table_1;
SELECT * FROM is an example of using SELECT with a clause. Other keywords and clauses include:
* The FROM clause
* The WHERE clause
* The GROUP BY clause
* The HAVING clause
* The ORDER BY clause
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