选择星期几是今天的星期几

Question

I am using Teradata and working on a SQL statement. I have a table where an attribute is "day_of_week". Sunday is 1, Monday is 2 etc.

I would like to select only the rows where day_of_week is the same as today. For ex, today is a Thursday (day 5) so I would like to select where day_of_week =5. Tomorrow is Friday, I will want to select where day = 6.

I know how to compute the day of the week corresponding to today : select sc.day_of_week from sys_calendar.calendar sc where sc.calendar_date = current_date

But I cannot use such a statement in the where clause of another select statement.

How would you go about solving my problem ?

Answer 1

What is you TD release? Since 13.10 there's a day_of_week function (which has been renamed to td_day_of_week in TD14):

WHERE day_of_week = td_day_of_week(current_date);

Answer 2

You can use such a statement in the where clause of another query, using a subquery:

where day_of_week = (select sc.day_of_week
                     from sys_calendar.calendar sc
                     where sc.calendar_date = current_date
                    )