declare @d datetime;
set @d='2012-03-31';

SELECT
    SUM(CASE WHEN 日期 BETWEEN CONVERT(varchar(8),@d,120)+'01'
           AND DATEADD(day,-1,DATEADD(month,1,CONVERT(varchar(8),@d,120)+'01'))
          THEN 数量 ELSE 0 END) AS 本月数量,
    SUM(CASE WHEN 日期 BETWEEN CONVERT(varchar(5),@d,120)+'01-01'
           AND CONVERT(varchar(5),@d,120)+'12-31'
          THEN 数量 ELSE 0 END) AS 本年数量,
    SUM(CASE WHEN 日期 BETWEEN CONVERT(varchar(8),@d,120)+'01'
           AND DATEADD(day,-1,DATEADD(month,1,CONVERT(varchar(8),@d,120)+'01'))
          THEN 单价*数量 ELSE 0 END) AS 本月金额,
    SUM(CASE WHEN 日期 BETWEEN CONVERT(varchar(5),@d,120)+'01-01'
           AND CONVERT(varchar(5),@d,120)+'12-31'
          THEN 单价*数量 ELSE 0 END) AS 本年金额
FROM tb