How to combine year,month,day to year-month-day?

[Zihan Dong]

Hi,
I'd like to use year, month, day to generate a new variable datenew (showing below).

id	year	month	day	datenew
1	2010	8	23	2010-8-23
2	2019	9	1	2019-9-1

Could anyone help with this? Thank you in advance!
Best,
Z

[Ali Atia]

gen datenew=mdy(month,day,year)
format datenew %tdCCYY-NN-DD

. list

     +--------------------------------------+
     | id   year   month   day      datenew |
     |--------------------------------------|
  1. |  1   2010       8    23   2010-08-23 |
  2. |  2   2019       9     1   2019-09-01 |
     +--------------------------------------+

Would recommend reading the contents of -help datetime-, which describe in detail how to do this and many other procedures to do with Stata's datetime format.

[Zihan Dong]

gen datenew=mdy(month,day,year)
format datenew %tdCCYY-NN-DD

. list

+--------------------------------------+
| id year month day datenew |
|--------------------------------------|
1. | 1 2010 8 23 2010-08-23 |
2. | 2 2019 9 1 2019-09-01 |
+--------------------------------------+

Would recommend reading the contents of -help datetime-, which describe in detail how to do this and many other procedures to do with Stata's datetime format.

Thank you Ali, this is exactly what I want!