Apex SOQL Queries

Introduction to SOQL Queries

Salesforce Object Query Language (SOQL) is similar to SQL and is used exclusively for querying the Salesforce database. It allows developers to fetch data from Salesforce objects by writing queries that return lists of sObjects. In this guide, you'll learn how to construct and execute SOQL queries within Apex to retrieve data efficiently using bind variables.

Basic SOQL Query Syntax

SOQL queries begin with the SELECT keyword, followed by the fields you want to retrieve. You specify the object to query using the FROM keyword. Optionally, you can filter results using the WHERE clause and order them using ORDER BY.

Using Bind Variables in SOQL Queries

Bind variables are used in SOQL queries to securely pass user-supplied data into the query. This is crucial for preventing SOQL injection attacks. Bind variables are preceded by a colon (:) and can reference Apex variables.

Combining SOQL Queries with Apex Logic

SOQL can be integrated with Apex logic for more complex data operations. You can iterate over query results, apply business logic, and even perform DML operations based on query outcomes.

Best Practices for Writing SOQL Queries

• Limit the number of fields: Only select the fields you need to improve performance.
• Use selective filters: Ensure your WHERE clause is specific to reduce the amount of data returned.
• Leverage indexes: Use indexed fields in your WHERE clause to speed up query execution.
• Avoid using SELECT *: Always specify fields explicitly to avoid unnecessary data retrieval.