SOQL Explained
SOQL is structurally similar to SQL's SELECT statement but is purpose-built for Salesforce's object-relational data model. It supports parent-to-child and child-to-parent relationship queries, aggregate functions (COUNT, SUM, AVG, MIN, MAX), GROUP BY and HAVING clauses, and polymorphic fields via TYPEOF. Queries can filter on virtually any indexed field, and developers should design queries to be selective (meaning they leverage indexed fields) to avoid full table scans on large objects.
SOQL is used in Apex code, the Developer Console, Workbench, the REST API, and data migration tools like Data Loader. Governor limits cap the number of SOQL queries per transaction at 100 (synchronous) or 200 (asynchronous), so efficient query design is critical. Clientell's free SOQL Generator lets you build complex queries visually and instantly copy them into your dev environment, saving time and reducing syntax errors.