Question

我还不是大学生，我正在努力进行一些日期计算。我的源代码中包含以下代码段：

LET dtRefDate = TODAY;

IF extend( CURRENT, hour to hour ) BETWEEN '06' AND '23'  THEN LET
   dtRefDate = TODAY+1;
END IF;

有人可以请我解释一下扩展功能做什么吗？ CURRENT和TODAY有什么区别？我不理解与IBM官方文档的区别。谢谢

Answer 1

TODAY返回DATE值，CURRENT返回DATETIME（年份到分数（3））值。

EXTEND用于提取DATE或DATETIME值的各个部分。

看下面的例子：

> select CURRENT from table(set{1});
(expression)
2019-09-29 10:07:12.000
1 row(s) retrieved.

> select TODAY from table(set{1});
(expression)
09/29/2019
1 row(s) retrieved.

> select extend(TODAY,year to year) from table(set{1});
(expression)
2019
1 row(s) retrieved.

> select extend(TODAY,month to day) from table(set{1});
(expression)
09-29
1 row(s) retrieved.

> select extend(CURRENT,hour to minute) from table(set{1});
(expression)
10:08
1 row(s) retrieved.

>

Informix中的CURRENT和TODAY有什么区别

1 个答案: