help on counting with multiple criterias

[Sera Sarkar]

Hello, I am new to Stata hence excuse my basic questions.
I have the following data set(example). I want to calculate the count of a particular permno for a particular value of t. Eg: how many permno "123" are there for t=1,t=2 etc separately and store it in a third column. I want to count this for all permno. Kindly help. I tried using count if but it is giving me total count.

permno	t
123	1
123	1
312	1
312	1
123	2
312	2
456	2
456	2
123	2
456	2
123	3
312	3
312	3
123	4
312	4
312	4
312	4
456	4
312	5

[Øyvind Snilsberg]

bysort t permno: gen wanted = _N

[Sera Sarkar]

Hi, Thank you for the response.
this code does not seem to work as am getting 1 for every row(which is not the case).

[Sera Sarkar]

Sorry, the code worked now. my data had got corrupted which showed all values as 1. Thank you so much for the responce.
Have a great day.