Question

我正在尝试重构一个在DB2 / iSeries上运行的MySQL查询，并且出现错误消息：使用标记的持续时间无效。

查看文档，我觉得下面的用法应该可以使用。

我想念什么吗？

SELECT
    IFNULL(SUM(CASE WHEN CURDATE() BETWEEN n.start_date AND n.expire_date
                    THEN 1 ELSE 0 END), 0) AS current,
    IFNULL(SUM(CASE WHEN CURDATE() -  365 DAY BETWEEN n.start_date AND n.expire_date
                    THEN 1 ELSE 0 END), 0) AS prior,
    IFNULL(SUM(CASE WHEN '2018-12-31' -  7 DAY BETWEEN n.start_date AND n.expire_date
                    THEN 1 ELSE 0 END), 0) AS full
FROM salesnumbers;

Answer 1

问题可能出在您的日期间隔上。尝试使用CURRENT DATE代替CURDATE()。另外，您可以直接在DB2中列出日期间隔+/-一定数量。

SELECT
    COUNT(CASE WHEN CURRENT DATE BETWEEN n.start_date AND n.expire_date
               THEN 1 END) AS current,
    COUNT(CASE WHEN CURRENT DATE -  1 YEAR BETWEEN n.start_date AND n.expire_date
               THEN 1 END) AS prior,
    COUNT(CASE WHEN DATE('2018-12-31') - 7 DAY BETWEEN n.start_date AND n.expire_date
               THEN 1 END) AS full
FROM salesnumbers;

请注意，我用条件计数替换了您的条件和。这使代码更加简洁，因为我们不必拼出明确的ELSE条件（默认为NULL）。

DB2使用带标签的持续时间不适用于多个日期间隔

1 个答案: