Calculate_Age_From_Date_In_SQL.md

On MS SQL Server

to Accurately calcutalte the age of something this works for most situations

SELECT
  FLOOR( --floor function returns age in years
    CAST( DATEDIFF( DAY, /*StartDate*/ , /*EndDate*/ ) AS DEC(38,16) ) / CAST(365.2425 AS DEC(38,16)) 
  ) As AgeInYears

FROM SomeTable

Example 1:

calculate age from current date using GETDATE

SELECT
  FLOOR( CAST( DATEDIFF( DAY, e.BirthDate , GETDATE() ) AS DEC(38,16) ) / CAST(365.2425 AS DEC(38,16)) ) As AgeInYears

FROM Employees AS e

Example 2:

Calculate age from a specific date using DATEFROMPARTS

SELECT
  FLOOR( CAST( DATEDIFF( DAY, p.ReleaseDate , DATEFROMPARTS(3030,3,11) ) AS DEC(38,16) ) / CAST(365.2425 AS DEC(38,16)) ) As AgeInYears

FROM Products as p

Other Helpful Links

• Gregorian Calendar 365.2425
• FLOOR
• DATEDIFF
• CAST
• Division