Use the Salesforce Object
Query Language (SOQL) to construct simple but powerful query strings
in the following environments:
In the queryString parameter in the query() call
In Apex statements
In Visualforce controllers and getter methods
In the Schema Explorer of the Force.com IDE
Similar to the SELECT command in Structured Query Language (SQL),
SOQL allows you to specify the source object (such as Account), a list of fields to retrieve, and conditions for selecting
rows in the source object.
SOQL uses the SELECT statement combined
with filtering statements to return sets of data, which may optionally
be ordered:
SELECT one or more fields
FROM an object
WHERE filter statements and, optionally, results are ordered
For example, the following SOQL query returns the value of the Id and Name field for all Account
records if the value of Name is Sandy: