MONTH (Transact-SQL)

date

Is an expression that can be resolved to a time, date, smalldatetime, datetime, datetime2, or datetimeoffset value. The date argument can be an expression, column expression, user-defined variable, or string literal.

int

MONTH returns the same value as DATEPART (month, date).

If date contains only a time part, the return value is 1, the base month.

The following statement returns 4. This is the number of the month.

SELECT MONTH('2007-04-30T01:01:01.1234567 -07:00');

The following statement returns 1900, 1, 1. The argument for date is the number 0. SQL Server interprets 0 as January 1, 1900.

SELECT YEAR(0), MONTH(0), DAY(0);

Reference