In this post we will learn how to calculate age from date of birth in sql. We can calculate diferent ways. We must use date functions for this. We will use getdate() function to learn current date, we’ll use year function to get year of a date or we’ll use datediff function to get difference of two year. We’ll write example queries from the library database. You can download it from the link below.
TO DOWNLOAD THE SAMPLE LİBRARY DATABASE CLICK
Example Queries
Example-1: List all students name, surname and age
1 | Select name,surname,year(getdate())-year(birthDate) as age from students |
or
1 | Select name,surname,datediff(YY,birthDate,getdate()) as age from students |
Result
505 rows listed.
Example-2: List all students name, surname and age sorted by their age
1 | Select name,surname,year(getdate())-year(birthDate) as age from students order by age |
or
1 | Select name,surname,datediff(YY,birthDate,getdate()) as age from students order by age |
Result
505 rows listed.
Example-3: How old was the student named Ali Al when he has got the last book
1 2 | Select name,surname from students where (year(getdate())-year(birthDate)) = 17 |
or
1 2 | Select name,surname from students where datediff(YY,birthDate,getdate()) = 17 |
Result
136 rows listed.
Example-4: List the name and surname of students whose age 17
1 2 3 4 5 | Select top 1 name,surname, (year(takenDate)-year(birthDate)) from students join borrows on students.studentId = borrows.studentId where name = 'Alfie' and Surname='Watson' order by takenDate desc |
or
1 2 3 4 5 | Select top 1 name,surname, datediff(YY,birthDate,takenDate) from students join borrows on students.studentId = borrows.studentId where name = 'Alfie' and Surname='Watson' order by takenDate desc |
Result
1 row listed.
