Case 1: From String to Stata format
This blog post discusses the conversion of text into Stata date. Once you have read this post, then you can read another post that lists a quick table of dates conversions from one frequency to another. Usually, when we import data manually into the Stata Editor, the dates are shown in string format. For example, Nov202011, November202011, or etc. We can use the gen command with date function
gen newdate = date(oldDate, "MDY")
Case 2: From daily to monthly
gen monthly = mofd(daily_date)
Case 3: From daily to weekly
gen monthly = wofd(daily_date)
Case 4: From daily to quarterly
gen monthly = qofd(daily_date)
Case 5: From daily to yearly
gen monthly = year(daily_date)
Case 6: From monthly to daily
If our date is recorded in monthly numeric format such as 2001m1, 2001m2, etc, then:
gen daily = dofm(monthly_date)