This year, this month, and this week

Select * From TBL where datepart (wk, date_field) = datepart (wk, getdate () and datepart (yyyy, date_field) = datepart (yyyy, getdate () -- week
Select * From TBL where datepart (M, date_field) = datepart (M, getdate () and datepart (yyyy, date_field) = datepart (yyyy, getdate () -- month
Select * From TBL where datepart (Q, date_field) = datepart (Q, getdate () and datepart (yyyy, date_field) = datepart (yyyy, getdate () -- quarter
Select * From TBL where datepart (yyyy, date_field) = datepart (yyyy, getdate () -- year

Quotation marks such as access wk "wk"

What is getdate ()? Can it be replaced by date?
The SQL statement cannot be replaced by date ().
It is equivalent to now ()

Example of a week
Select * from table where datediff (Week, time field, getdate () = 0

Note that datediff uses Sunday as the first day of a week.
That is, the value of datediff (Week, '2017-07-27 ', '2017-08-01') is 0.

If you want to use Monday as the first day of a week, use:
Select * from table where datediff (Week, time field + 1, getdate () + 1) = 0

// ================================================ ======================================= //

1. The first day of a month
Select dateadd (mm, datediff (mm, 0, getdate (), 0)

2. This Monday
Select dateadd (wk, datediff (wk, 0, getdate (), 0)
Select dateadd (wk, datediff (wk, 0, getdate (), 6)

 

3. The first day of the year
Select dateadd (YY, datediff (YY, 0, getdate (), 0)

4. The first day of the quarter
Select dateadd (QQ, datediff (QQ, 0, getdate (), 0)

5. midnight of the day
Select dateadd (DD, datediff (DD, 0, getdate (), 0)

6. Last day of last month
Select dateadd (MS,-3, dateadd (mm, datediff (mm, 0, getdate (), 0 ))

7. Last day of last year
Select dateadd (MS,-3, dateadd (YY, datediff (YY, 0, getdate (), 0 ))

8. Last day of the month
Select dateadd (MS,-3, dateadd (mm, datediff (M, 0, getdate () + 1, 0 ))

9. The last day of the year
Select dateadd (MS,-3, dateadd (YY, datediff (YY, 0, getdate () + 1, 0 ))

10. the first Monday of this month
Select dateadd (wk, datediff (wk, 0, dateadd (DD, 6-datepart (day, getdate (), getdate (), 0)

 

11. query the number of registrants registered this week
Select count (*) from [user] Where datediff (Week, create_day-1, getdate () = 0

12. Number of registrants last week
Select count (*) from [user] Where datediff (Week, create_day-1, getdate () = 1

13. Number of registrants this month
Select count (*) from [user] Where datediff (month, create_day, getdate () = 0

14. Number of registrants last month
Select count (*) from [user]
Where datediff (month, create_day, getdate () = 1

If efficiency is required, write the query in this way.

1. query the number of registrants registered this week
Select count (*) from [user]
Where create_day> = dateadd (day, 2-datepart (weekday, getdate (), convert (varchar, getdate (), 112 ))
And create_day <dateadd (day, 9-datepart (weekday, getdate (), convert (varchar, getdate (), 112 ))

2. Number of registrants last week
Select count (*) from [user]
Where create_day> = dateadd (day,-5-datepart (weekday, getdate (), convert (varchar, getdate (), 112 ))
And create_day <dateadd (day, 2-datepart (weekday, getdate (), convert (varchar, getdate (), 112 ))

3. Number of registrants this month
Select count (*) from [user]
Where create_day> = dateadd (day, 1-day (getdate (), convert (varchar, getdate (), 112 ))
And create_day <dateadd (month, 1, dateadd (day, 1-day (getdate (), convert (varchar, getdate (), 112 )))

4. Number of registrants last month
Select count (*) from [user]
Where create_day> = dateadd (month,-1, dateadd (day, 1-day (getdate (), convert (varchar, getdate (), 112 )))
And create_day <dateadd (day, 1-day (getdate (), convert (varchar, getdate (), 112 ))

5. This week
Select count (*) from user
Where datediff (DD, create_day, getdate () <= datepart (DW, getdate ())

6. Last week
Select count (*) from user
Where datediff (DD, create_day, (getdate ()-datepart (DW, getdate () <= 7

7. This month
Select count (*) from user
Where datepart (mm, create_day) = datepart (mm, getdate ())

8. Last month
Select count (*) from user
Where datepart (mm, create_day) = datepart (mm, getdate ()-1

9. This week
Select count (*) from [user]
Where datediff (DD, create_day, getdate () <= datepart (DW, getdate ())

10. Last week
Select count (*) from [user]
Where datediff (DD, create_day, (getdate ()-datepart (DW, getdate () <= 7

11. This month
Select count (*) from [user]
Where datepart (mm, create_day) = datepart (mm, getdate ())
12. Last month
Select count (*) from [user]
Where datepart (mm, create_day) = datepart (mm, getdate ()-1

 

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