When a SQL query is executed, the database does not run it directly.
The SQL engine follows internal steps to process the query.
This process is called query execution flow.
First, the SQL parser checks query syntax.
If syntax is invalid, execution stops immediately.
Only valid queries move forward.
After parsing, the optimizer creates an execution plan.
The optimizer decides how data should be retrieved.
It selects indexes or table scans.
The execution engine runs the chosen plan.
Rows are fetched, filtered, and returned.
Only required data is processed.
Understanding query execution helps optimize performance.
It explains why indexes are important.
This knowledge is critical for backend developers.