Merging dataset with different dates

[Raul Athwall]

Hi, I want to add data from my csv file to my main data file in STATA. The csv file goes from 1988-2017 and my main data file goes from 2004-2022. I only want values from 2004-2017 in my csv to merge into my main data file in STATA. How would I go about doing this?

[Andrew Musau]

The merge command has a -keep- option, so you can specify

merge 1:1 id year using ..., keep(match)

In this case, the intersection between 1988-2017 and 2004-2022 is exactly 2004-2017.

See

help merge

[Raul Athwall]

Do I need to import my csv into stata or can it merge from the csv?

[Raul Athwall]

Never mind about post #3- I have sorted this.

I am encountering this issue of trying to match the dates- the variable "date" is the same in both files

 merge 1:1 date using "/Users/raulathwall/OneDrive/Dis STATA/Fama French factors.dta"
variable date does not uniquely identify observations in the master data
r(459);

I am trying to merge this onto my master file

[Andrew Musau]

As long as date uniquely identifies observations in the using dataset

merge m:1

should work.

[Raul Athwall]

date    cost    cheap    donation    asset
1/1/2004    10    70    0    0
1/2/2004    15    75    0    6
1/3/2004    10    65    0    0
1/4/2004    11    76    0    0
1/5/2004    0    44    0    0
1/6/2004    15    74    0    15
1/7/2004    10    67    5    15
1/8/2004    16    64    0    14
1/9/2004    15    58    3    11
1/10/2004    14    79    0    0

This is what the master dataset looks like, and it still gives me the same error

With the dataset I want to merge the dates are in the same format e.g. 1/1/2004, but all the days do not coincide together as this is financial data so I do not have weekend data so I want these to be missing values when merged in

[Andrew Musau]

Check why you have duplicates, or show the results of

bys date: gen tag=_N>1
dataex if tag

across both datasets.