当天数据：select * from tableName where datediff(day, 字段名,getdate())=0
本周数据：select * from tableName where datediff(week, 字段名,getdate())=0
本月：select * from tableName where datediff(month, 字段名,getdate())=0
本季度：内select * from tableName where datediff(quarter, 字段名,getdate())=0
本年：select * from tableName where datediff(year, 字段名,getdate())=0