6 methods override Query::execute() in Drupal 7

DeleteQuery::execute in includes/database/query.inc

Executes the DELETE query.

InsertQuery::execute in includes/database/query.inc

Executes the insert query.

MergeQuery::execute in includes/database/query.inc

Runs the query against the database.

SelectQuery::execute in includes/database/select.inc

Runs the query against the database.

TruncateQuery::execute in includes/database/query.inc

Executes the TRUNCATE query.

UpdateQuery::execute in includes/database/query.inc

Executes the UPDATE query.