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案例讨论:Oracle两表连接

  【IT168 服务器学院】Oracle的两表连接怎么实现,原来是SQL的现在想换成oracle的,SQL的如下:

  SELECT COUNT(*) AS COUNT, SUM(timelen) AS totlekeeptime, SUM(moneys) AS totletimefee, SUM(realmoneys) AS totlenewfee, areacode.area_name FROM phonedata INNER JOIN areacode ON LEFT(phonedata.ani, LEN(areacode.area_code)) = areacode.area_code WHERE starttime>''2005-12-27 00:00:00'' and starttime<''2005-12-27 23:59:59'' and endtime is not null and userid like ''001136'' GROUP BY areacode.area_name order by totlekeeptime

  oracle里该怎么办呢?

  讨论一:

  SELECT AREACODE.AREA_NAME,COUNT(*) AS COUNT,

  SUM(TIMELEN) AS TOTLEKEEPTIME,

  SUM(MONEYS) AS TOTLETIMEFEE,

  SUM(REALMONEYS) AS TOTLENEWFEE,

  FROM PHONEDATA INNER JOIN AREACODE ON (LEFT(PHONEDATA.ANI,LEN(AREACODE.AREA_CODE)) = AREACODE.AREA_CODE)

  WHERE STARTTIME>''2005-12-27 00:00:00''

  AND STARTTIME<''2005-12-27 23:59:59''

  AND ENDTIME IS NOT NULL

  AND USERID LIKE ''001136%''

  GROUP BY AREACODE.AREA_NAME

  ORDER BY TOTLEKEEPTIME

  /

  说明:只是不知道你没有限定哪个表的那些字段是不是只有一个表里面有,如果不是,会报错的。

  点评:有错误:

  1.oracle里两表连接不是用INNER JOIN AREACODE ON 而是用外连接LEFT OUTER JOIN .. ON或内连接LEFT in JOIN .. ON

  2.oracle里没有LEFT函数,取字接数是用length;

  讨论二:

  SELECT AREACODE.AREA_NAME,COUNT(*) AS COUNT,

  SUM(TIMELEN) AS TOTLEKEEPTIME,

  SUM(MONEYS) AS TOTLETIMEFEE,

  SUM(REALMONEYS) AS TOTLENEWFEE,

  FROM PHONEDATA ,AREACODE

  where substring(PHONEDATA.ANI,1,length(AREACODE.AREA_CODE)) = AREACODE.AREA_CODE

  and to_date(STARTTIME,''yyyy-mm-dd hr24:mi:ss'')>''2005-12-27 00:00:00''

  AND to_date(STARTTIME,''yyyy-mm-dd hr24:mi:ss'')<''2005-12-27 23:59:59''

  AND ENDTIME IS NOT NULL

  AND USERID LIKE ''001136%''

  GROUP BY AREACODE.AREA_NAME

  ORDER BY TOTLEKEEPTIME

  点评:两表连接那错了,但这地方: substring(PHONEDATA.ANI,1,length(AREACODE.AREA_CODE)) = AREACODE.AREA_CODE是对的;

  非常好的答案:

  SELECT COUNT(*) AS COUNT, SUM(timelen) AS totlekeeptime, SUM(moneys) AS totletimefee,

  SUM(realmoneys) AS totlenewfee, areacode.area_name

  FROM phonedata ,areacode

  WHERE starttime>''2005-12-27 00:00:00'' and starttime<''2005-12-27 23:59:59''

  and endtime is not null and userid like ''001136''

  /*and LEFT(phonedata.ani, length(areacode.area_code)) = areacode.area_code */

  and substr(phonedata.ani, 1,length(areacode.area_code)) = areacode.area_code

  GROUP BY areacode.area_name order by totlekeeptime

  说明:inner join 直接相等就可以了,left换成substr。

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