每个币种取最近3次导进来的记录

select EFFECTIVE_DATE,  
       CCY_CODE,
     RATE
   from RATE_SHEET
   where LOCATION = @loc
    and exists(select count(1)
      from RATE_SHEET tmp
      where tmp.LOCATION = @loc
       and tmp.CCY_CODE = MM_CALLRATE_SHEET.CCY_CODE
       and tmp.LOAD_DATE > MM_CALLRATE_SHEET.LOAD_DATE
       having count(1) < 4)
   order by CCY_CODE asc, EFFECTIVE_DATE desc

 

解析：

AUD  2012-12-12

AUD  2012-12-11

AUD  2012-12-10

AUD  2012-12-09

AUD  2012-12-08

08的记录有4条大于记录， 所以不显示。