tsql - Subtracting dates in SQL Server

Question

I am trying to convert a PostgreSQL query to a T-SQL query, and I can not get the syntax correct for this PostgreSQL line:

ROUND(CAST((CURRENT_DATE - setupdate) AS decimal) /365,1) AS RetentionYears

When converting it to T-SQL, I have tried this

ROUND(CAST((GETDATE() - setupdate) AS Decimal) / 365, 1) AS RetentionYears

But when I run that I get the error

Msg 402, Level 16, State 1, Line 43
The data types datetime and date are incompatible in the subtract operator.

What would be the proper way to write that statement in T-SQL?

question from:https://stackoverflow.com/questions/65866806/subtracting-dates-in-sql-server

Answer 1

You want datediff():

DATEDIFF(year, current_timestamp, setupdate) As RetentionYears