doc/user/content/sql/execute.md
EXECUTE plans and executes prepared statements. Since prepared statements only last the duration of a session, the statement must have been prepared during the current session.
If the PREPARE statement specified some parameters, you must pass values compatible with those parameters to EXECUTE. Values are considered compatible here when they can be assignment cast. (This is the same category of casting that happens for INSERT.)
{{% include-syntax file="examples/execute" example="syntax" %}}
The following example prepares a statement a and runs it
using the EXECUTE statement:
PREPARE a AS SELECT 1 + $1;
EXECUTE a (2);
All prepared statements will be cleared at the end of a session. You can also
explicitly deallocate the statement using DEALLOCATE.