统计指定时间段内生日的用户
DECLARE @startTime datetime, @endTime datetime
SELECT @dt1='2018-03-01',@dt2='2018-03-10'
SELECT * FROM 表名
WHERE DATEADD(Year,DATEDIFF(Year,birth_date,@dt1),生日字段) BETWEEN @startTime AND @endTime
OR DATEADD(Year,DATEDIFF(Year,birth_date,@dt2), 生日字段) BETWEEN @startTime AND @endTime
备注:后面有加了 or 是防止跨年查询