--320, SQL SERVER  日报--查询2009-01-01当天客户A1,A2,A3的订单数量SELECT Cust_Name     , CONVERT(CHAR(10), Order_Date, 120) Order_Date     , SUM(Qty) QtyFROM Orders_BigWHERE 1=1     AND Cust_Name IN ('A1', 'A2', 'A3')     AND Order_Date >= '2009-01-01'      AND Order_Date<'2009-01-02'     /*AND Order_Date  -- BETWEEN...AND相当于>=和<=            BETWEEN '2009-01-01'                 AND '2009-01-02'*/GROUP BY Cust_Name     , CONVERT(CHAR(10), Order_Date, 120)ORDER BY 2, 1--321. ORACLE 日报--查询2009-01-01当天客户A1,A2,A3的订单数量SELECT Cust_Name  , TO_CHAR(Order_Date, 'YYYY-MM-DD') Order_Date --方法一:转换成字符串类型  --, TRUNC(Order_Date) Order_Date  --方法二:将时分秒信息截断  , SUM(Qty) QtyFROM Orders_BigWHERE 1=1     AND Cust_Name IN ('A1', 'A2', 'A3')     AND Order_Date >= DATE'2009-01-01'      AND Order_Date
    
     = '2009-01-01'    AND Order_Date<'2009-02-01'GROUP BY Cust_Name        , CONVERT(CHAR(7), Order_Date, 120)ORDER BY 2, 1--326, ORACLESELECT Cust_Name    , TO_CHAR(Order_Date, 'YYYY-MM') Order_YrMs --方法1    --, TRUNC(Order_Date, 'MM') Order_Date--方法2    , SUM(Qty) QtyFROM Orders_BigWHERE 1=1    AND Cust_Name IN ('A1', 'A2', 'A3')    AND Order_Date >= DATE'2009-01-01'     AND Order_Date