在postgresql函数中捕获select查询返回值并使用它

Question

我想执行这个函数。但它得到了错误说

ERROR:

syntax error at or near ":="

LINE 7: select result:=MAX(path_history_id)as path INTO result from...

在这个功能我想：

1. 执行select with (MAX)，它会从表中返回最大ID;
2. 捕获该值（它是一个整数值）;
3. 将该值放入最后选择查询的条件。

我不能在postgresql找到一种方法来做到这一点。

CREATE OR REPLACE FUNCTION memcache(IN starting_point_p1 character varying, IN ending_point_p1 character varying) 

RETURNS TABLE(path integer, movement_id_out integer, object_id_fk_out integer, path_history_id_fk_out integer, walking_distance_out real, angel_out real, direction_out character varying, time_stamp_out timestamp without time zone, x_coordinate_out real, y_coordinate_out real, z_coordinate_out real) AS 
$BODY$ 
    DECLARE result int; 
    BEGIN 

    select result:=MAX(path_history_id)as path INTO result from path_history_info where starting_point=starting_point_p1 and ending_point =ending_point_p1 and achieve='1'; 
    return query 
    select * from movement_info where path_history_id_fk=result;  
    END; 
    $BODY$ 
    LANGUAGE plpgsql 

Answer 1

语法错误

你的函数中的第一个查询需要进行如下更改：

select MAX(path_history_id)as path INTO result 
    from path_history_info 
    where starting_point=starting_point_p1 
    and ending_point =ending_point_p1 and achieve='1'; 

单个查询

你实际上并不需要一个存储过程。一个查询可以达到相同的结果。

select * from movement_info where path_history_id_fk = 
(SELECT MAX(path_history_id) FROM path_history_info 
    where starting_point=starting_point_p1 
    and ending_point =ending_point_p1 and achieve='1';