There is no straightforward way to find leap year in SQL Server. We have to use our own logic to find whether the given year is leap or not. Here I have gone through couple of methods to find the the leap year.

## 1. February Extra Day Method

In this method we will be checking whether the February month of the year has 29 days. If yes then we can say it’s a leap year. Here is the script:

```
DECLARE @GivenYear varchar(4)
SET @GivenYear = '1904'
SELECT
CASE DATEPART(month,
DATEADD(day, 1,
CAST((@GivenYear + '-02-28')
as datetime)))
WHEN 2
THEN 1
ELSE 0
END
GO
```

## 2. Leap Year Rule Method

In this method we will apply the standard leap year rule and create a logic to identify the leap year. The rules or algorithm of leap year is:

- 4th year test: If year is divisible by 4.
- 100th year test: And, if year is not divisible by 100.
- 400th year test: Or, if year is divisible by 400.

```
DECLARE @GivenYear int
SET @GivenYear = 1900
IF ((@GivenYear % 4 = 0 AND @GivenYear % 100 <> 0)
OR @GivenYear % 400 = 0)
SELECT 1
ELSE
SELECT 0
GO
```

## Reference

- About leap year algorithm at Wikipedia.
- More SQL Server Tips.