访问 SQL 查询 - 从每月的特定日期选择日期范围

Question

I have been scratching my head over this for a while, but i would like to make a query that selects values from the 24th of the current / last month to the 24th of the next/current month depending on the month we are in - this is basically from one payroll to the next. any suggestions on the SQL query?

So for instance - if the current date is the 20th March then i would want all data from 24th Feb to the 24th March, but if the date was over the 24th of this month say 30th March then i would want data from 24th March to 24th April - if that makes sense.

Thanks, Phill

Answer 1

Just subtract 23 days and extract the year and the month:

select year(dateadd("d", -23, datecol)) as year,
       month(dateadd("d", -23, datecol)) as month

Answer 2

With this expression:

iif(
  day(date()) >= 24,
  dateserial(year(date()), month(date()), 24),
  dateserial(year(dateadd('m', -1, date())), month(dateadd('m', -1, date())), 24)
)

you can get the starting date of your condition (though I'm not sure about the >= sign, maybe it should by just > ? ), so use it like this:

select t.col1, t.col2, ... 
from (
  select *, 
    iif(
      day(date()) >= 24,
      dateserial(year(date()), month(date()), 24),
      dateserial(year(dateadd('m', -1, date())), month(dateadd('m', -1, date())), 24)
    ) as start_date
  from tablename
) as t
where t.date_column between t.start_date and dateadd('m', 1, t.start_date)

Answer 3

For a slimmer method, use DateAdd and DateDiff :

Select *
From YourTable
Where DateDiff('m', DateAdd('d', -23, [YourDateField]), DateAdd('d', -23, Date())) = 0