Question

我需要得到C ='1'的前两行，我正在通过TimeStamp Descending命令查询，我不想要要查询的最后一行

    A      B  C   TimeStamp
 ------------------------------------
  foo    one  1   20180405153936
  foo    two  1   20180405153936
  foo    two  2   20180405115417
  foo    one  2   20180405115053
  foo  three  1   20180405113923

Answer 1

您可以使用ROWNUM构造，但请记住，除非您打包排序选择，否则ROWNUM将按行添加到表中的顺序返回行。

SELECT * FROM
    (SELECT * FROM 
         yourTable
     WHERE C = 1 
     ORDER BY "TimeStamp" DESC)
WHERE ROWNUM <= 2

编辑

鉴于添加的信息，以下内容可能比使用ROWNUM更好。

SELECT * FROM 
    yourTable
WHERE 
    C = 1 AND 
    "TimeStamp" > (
        SELECT MIN("TimeStamp") FROM yourTable WHERE C = 1
    ) 
ORDER BY "TimeStamp" DESC

Answer 2

您可以使用ROWNUM

SELECT * FROM
(SELECT * FROM 
     Table1 
 WHERE C=1
 ORDER BY "TimeStamp" DESC)
WHERE ROWNUM <= (SELECT COUNT(*) FROM Table1 WHERE C=1)-1

<强>演示

http://sqlfiddle.com/#!4/08ed98/11

获得满足条件的前几行

2 个答案: