Oracle取TOP N条记录

在SQL Server里面有top关键字可以很方便的去前N条记录，但是Oracle里面却没有，常用的简单的使用方法如下，： 方法1：利用ROW_NUMBER函数

SELECT NO FROM (
    SELECT ROW_NUMBER() OVER (ORDER BY NO) RNO, NO FROM ROWNUM_TEST
)
WHERE RNO <= 5
ORDER BY NO ;

取出中间 n 条记录

SELECT NO FROM (
    SELECT ROW_NUMBER() OVER (ORDER BY NO) RNO, NO FROM ROWNUM_TEST
)
WHERE RNO BETWEEN 5 AND 10
ORDER BY NO;

方法2：利用子查询

SELECT NO FROM (
    SELECT NO FROM ROWNUM_TEST
    ORDER BY NO
)
WHERE ROWNUM <= 5
ORDER BY NO ;

取出中间 n 条记录

SELECT NO  FROM (
    SELECT NO, ROWNUM RNO FROM (
        SELECT NO FROM ROWNUM_TEST
        ORDER BY NO
    )
) WHERE RNO BETWEEN 5 AND 10
ORDER BY NO;