Question

我正在尝试声明一个名为NEW_VARIABLE的变量，它等于(end_date - start_date)。然后我使用下面的变量NEW_VARIABLE作为间隔(date1 + NEW_VARIABLE + interval '1 days')。

CREATE TEMPORARY TABLE tmp1_variables AS (
    SELECT
        '2016-10-29'::date as start_date,
        dateadd(day,-10,getdate())::date as end_date,
        '2015-10-31'::date as date1
        (end_date - start_date) as NEW_VARIABLE
);

DROP TABLE IF EXISTS tmp_tbl1;
CREATE TEMPORARY TABLE tmp_tbl1 (cobrand_id int, xsum numeric(30,15));

insert into tmp_tbl1 (cobrand_id, xsum )
select q1.cobrand_id, q1.a/q2.d as xsum from (
    SELECT cobrand_id, sum(calc) AS a FROM jwn_calc s, tmp1_variables
    where s.optimized_transaction_date > start_date AND s.optimized_transaction_date <= end_date + interval '1 days' GROUP BY cobrand_id
) as q1
inner join (
    SELECT cobrand_id AS c, 
    sum(CASE WHEN optimized_transaction_date > date1 AND optimized_transaction_date <= date1 + NEW_VARIABLE + interval '1 days' THEN Calc END) / 
    sum(CASE WHEN optimized_transaction_date > date1 AND optimized_transaction_date <= date1 + interval '91 days' THEN Calc END) AS d
    FROM jwn_calc, tmp1_variables
    GROUP BY cobrand_id
) as q2 on q1.cobrand_id = q2.c;

Answer 1

SQL中根本没有 no 变量。只是表格，列和表达。所以，显然你不能宣布一个变量＆＃34;首先。错误的术语很容易激发一种不恰当的方法......

另外，dateadd()和getdate()？你可能会想到MS SQL Server。 Postgres中不存在这些功能。

无论哪种方式，使用子查询（或CTE）从常量输入构建新表达式：

CREATE TEMP TABLE tmp1_variables AS (
SELECT *, end_date - start_date AS new_variable
FROM  (
   SELECT date '2016-10-29' AS start_date
        , CURRENT_DATE - 10 AS end_date
        , date '2015-10-31' AS date1
   ) sub
);

显示有效的Postgres语法。

在Postgres中，您只需在integer（但不是date）中添加/减去timestamp。如果您向interval添加date，则会获得timestamp。

当然，您可以将结果转回date：

(date1 + new_variable + interval '1 days')::date

而是计算一个date开头：

date1 + new_variable + 1

除此之外：在Postgres中将不带引号的标识符强制转换为小写。

在SELECT语句中声明变量

1 个答案: