带参数调用函数或视图

Question

我想创建功能或视图，每月显示特定年份的一些信息。

CREATE OR REPLACE VIEW name_view AS 
    SELECT d_name,
    SUM("Jan") "Jan",
    SUM("Feb") "Feb"
    ...
    FROM (
    select distinct d_name,
      COUNT(CASE WHEN EXTRACT (MONTH FROM h_date) = '01' THEN query_string ELSE NULL END) "Jan",
      COUNT(CASE WHEN EXTRACT (MONTH FROM h_date) = '02' THEN query_string ELSE NULL END) "Feb",
    ..
       from h
           inner join d on h_d = d_id
                WHERE EXTRACT (YEAR FROM h_date) = '2015' 
            GROUP BY  d_name) sub query
    GROUP BY d_name

没有

我怎么能这样调用视图

WHERE EXTRACT (YEAR FROM h_date) = '2015'

但是电话的年份呢？例如

SELECT * FROM name_view ('2015')

Answer 1

您应该在 SELECT 中使用 YEAR，当您从视图中选择时使用 WHERE year = 2015。

CREATE OR REPLACE VIEW name_view AS 
SELECT d_name,
SUM("Jan") "Jan",
SUM("Feb") "Feb",
YEAR,
....

视图的使用：

SELECT * 
FROM name_view 
WHERE year = '2015';

Answer 2

你可以试试这个函数传递日期作为参数：

CREATE OR REPLACE FUNCTION "show_info"("DATE" date)
  RETURNS SETOF show_info AS
$BODY$SELECT d_name,
    SUM("Jan") "Jan",
    SUM("Feb") "Feb"
    ...
    FROM (
    select distinct d_name,
      COUNT(CASE WHEN EXTRACT (MONTH FROM h_date) = '01' THEN query_string ELSE NULL END) "Jan",
      COUNT(CASE WHEN EXTRACT (MONTH FROM h_date) = '02' THEN query_string ELSE NULL END) "Feb",
    ..
       from h
           inner join d on h_d = d_id
                WHERE EXTRACT (YEAR FROM h_date) = $1 
            GROUP BY  d_name) subquery
    GROUP BY d_name
;$BODY$
  LANGUAGE sql VOLATILE
  COST 100
  ROWS 1000;

你可以这样称呼它

select * from show_info(date)

这里的日期将是您想要通过的任何日期