云数据库 GaussDB-DEALLOCATE:示例

时间：2025-02-12 15:07:58

云数据库 GaussDB

示例

  
       --查看现有预备语句。gaussdb=# SELECT name, statement, parameter_types FROM pg_prepared_statements; name | statement | parameter_types ------+-----------+-----------------(0 rows)--创建q1,q2,q3，q4四个预备语句。gaussdb=# PREPARE q1 AS SELECT 1 AS a;PREPAREgaussdb=# PREPARE q2 AS SELECT 1 AS a;PREPAREgaussdb=# PREPARE q3 AS SELECT 1 AS a;PREPAREgaussdb=# PREPARE q4 AS SELECT 1 AS a;PREPARE--再次查看现有预备语句。gaussdb=# SELECT name, statement, parameter_types FROM pg_prepared_statements; name |          statement           | parameter_types ------+------------------------------+----------------- q1   | PREPARE q1 AS SELECT 1 AS a; | {} q4   | PREPARE q4 AS SELECT 1 AS a; | {} q3   | PREPARE q3 AS SELECT 1 AS a; | {} q2   | PREPARE q2 AS SELECT 1 AS a; | {}(4 rows)--删除q4预备语句并查看剩余预备语句。gaussdb=# DEALLOCATE q4;gaussdb=# SELECT name, statement, parameter_types FROM pg_prepared_statements; name |          statement           | parameter_types ------+------------------------------+----------------- q1   | PREPARE q1 AS SELECT 1 AS a; | {} q3   | PREPARE q3 AS SELECT 1 AS a; | {} q2   | PREPARE q2 AS SELECT 1 AS a; | {}(3 rows）--删除所有预备语句并查看剩余预备语句。gaussdb=# DEALLOCATE ALL;DEALLOCATE ALLgaussdb=# SELECT name, statement, parameter_types FROM pg_prepared_statements; name | statement | parameter_types ------+-----------+-----------------(0 rows)