Sql Can'；t序列化临时记录类型postgres

我试图根据以下某些条件使计算动态化，但当我尝试将字段动态发送到我的计算逻辑时，它失败，错误为“无法序列化瞬态记录类型”：

Create table语句：

create table calculation_t(
    Id serial,
    product_id integer not null,
    metric_id integer not null,
    start_date date,
    end_date date,
    calculation_logic varchar(50),
    insert_timestamp timestamp default current_timestamp,
    CONSTRAINT calculation_pk PRIMARY KEY(Id),
    CONSTRAINT calculation_pid_fk FOREIGN KEY(product_id) REFERENCES Product_T(Product_id),
    CONSTRAINT calc_mid_fk FOREIGN KEY(metric_id) REFERENCES metric_T(metric_id)
    );

insert into calculation_t(product_id,metric_id,calculation_logic)
select a.product_id,b.metric_id,
(case when b.metric_id=2 then
('$1-$2') else
'$1/$2' end) calc
from product_t a,metric_t b

插入语句：

create table calculation_t(
    Id serial,
    product_id integer not null,
    metric_id integer not null,
    start_date date,
    end_date date,
    calculation_logic varchar(50),
    insert_timestamp timestamp default current_timestamp,
    CONSTRAINT calculation_pk PRIMARY KEY(Id),
    CONSTRAINT calculation_pid_fk FOREIGN KEY(product_id) REFERENCES Product_T(Product_id),
    CONSTRAINT calc_mid_fk FOREIGN KEY(metric_id) REFERENCES metric_T(metric_id)
    );

insert into calculation_t(product_id,metric_id,calculation_logic)
select a.product_id,b.metric_id,
(case when b.metric_id=2 then
('$1-$2') else
'$1/$2' end) calc
from product_t a,metric_t b

抛出上述错误的Select语句：

 select *,(1,2,calculation_logic) from calculation_t

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注意：我正在使用Greenplum数据库。

尝试从查询中删除括号：

select *,1,2,calculation_logic from calculation_t

这对我有用。

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Thanx，

我无法用PostgreSQL 8.4或9.3重现您的错误。确实要在SELECT语句中使用行构造函数吗？