发行说明

40.10 Appendix D. Extended Scalar Functions

40.10.1 Date and Time Functions

下列函数是“Appendix D. Extended Scalar Functions”的“Date and Time Functions”一节中所缺少的函数：

DAYOFWEEK_ISO( date_exp )

Returns the day of the week in date_exp as an integer value in the range 1-7, where 1 represents Monday. Note the difference between this function and the DAYOFWEEK() function, where 1 represents Sunday.

WEEK_ISO( date_exp )

Returns the week of the year in date_exp as an integer value in the range of 1-53. Week 1 is defined as the first week of the year to contain a Thursday. Therefore, Week1 is equivalent to the first week that contains Jan 4, since Monday is considered to be the first day of the week.

Note that WEEK_ISO() differs from the current definition of WEEK(), which returns a value up to 54. For the WEEK() function, Week 1 is the week containing the first Saturday. This is equivalent to the week containing Jan. 1, even if the week contains only one day.

DAYOFWEEK_ISO() 和 WEEK_ISO() 在版本 7 中创建的数据库中是自动提供的。如果数据库是在版本 7 之前创建的，则可能未提供这些函数。要使 DAYOFWEEK_ISO() 和 WEEK_ISO() 函数在这种数据库中可用，使用 db2updb 系统命令。有关 db2updb 的更多信息，参见《发行说明》中的“Command Reference”一节。