PREPARE
New in v0.9.7.
PREPARE creates a prepared statement by parsing the initial SELECT, INSERT, UPDATE, or DELETE statement. A subsequent EXECUTE statement then plans and executes the statement.
Syntax
| Field | Use |
|---|---|
| name | A name for this particular prepared statement that you can later use to execute or deallocate a statement. The name must be unique within a session. |
| statement | Any SELECT, INSERT, UPDATE, or DELETE statement. |
Details
Prepared statements can take parameters: values that are substituted into the statement when it is executed. The data type is inferred from the context in which the parameter is first referenced. To refer to the parameters in the prepared statement itself, use $1, $2, etc.
Prepared statements only last for the duration of the current database session. You can also delete them during a session with the DEALLOCATE command.
Examples
Create a prepared statement
PREPARE a AS SELECT 1 + $1;
Execute a prepared statement
EXECUTE a ('a', 'b', 1 + 2)
Deallocate a prepared statement
DEALLOCATE a;