Question

我正在尝试将Oracle迁移到Postgres。无论在Oracle中我们有批量收集功能，我都创建了纯SQL函数：喜欢

CREATE OR REPLACE FUNCTION get_pub_access_tax(a_person_id mobile_user.id%TYPE)
RETURNS TABLE (tax_id integer) AS 
$$
    WITH v_pub_tax AS (SELECT tax_id FROM mobile_pub_tax)
    select tax_id from v_pub_tax ;

$$ LANGUAGE sql;

但是Oracle中存在一种情况，即有条件地获取数据:(见下面的例子）

  FUNCTION get_st_tax(
    a_st_type IN VARCHAR2)
  RETURN mmt_array
  IS
   v_tax_list  mmt_array := mmt_array();
  BEGIN
    IF a_st_type = 'top-stories' THEN
      SELECT t.tax_id BULK COLLECT INTO v_tax_list
      FROM mobile_st_tax t;
      RETURN v_tax_list;
    ELSE
      SELECT t.tax_id BULK COLLECT INTO v_tax_list
      FROM mobile_st_tax t WHERE t.stream_type=a_stream_type;
      RETURN v_tax_list;
    END IF;
  END;

我们如何将以上Oracle代码转换为Postgres？

我尝试使用if条件但是语法错误（代码下面）。下面的代码我尝试在Postgres中执行，这给了我语法错误。

CREATE OR REPLACE FUNCTION get_st_tax ( a_st_type IN VARCHAR) 
RETURNS TABLE (tax_id integer) AS 
$$  
    IF a_stream_type = 'top-stories' THEN
        WITH v_tax_list AS (
        SELECT t.tax_id FROM mobile_st_tax t)
        SELECT tax_id FROM v_tax_list;
    ELSE
        WITH v_tax_list AS (
        SELECT t.tax_id FROM mobile_st_tax t WHERE t.stream_type=a_stream_type)
        SELECT tax_id FROM v_tax_list;   
    END IF;

$$ LANGUAGE SQL;

请帮助。

Answer 1

第二个函数可以在普通的sql中完成：

create function get_st_tax(a_st_type text)
returns int[] as $$
    select array_agg(t.tax_id)
    from mobile_st_tax t 
    where 
        t.stream_type = a_stream_type and a_st_type <> 'top_stories'
        or
        a_st_type = 'top-stories'
    ;
$$ language sql;

Postgres：条款

1 个答案: