rownum的用法oracle
时间:2021-07-01 10:21:17
帮助过:17人阅读
SELECT * FROM T WHERE ROWNUM=1 可以查询出来数据,
而SELECT * FROM T WHERE ROWNUM=2不可以查询出来数据。
in the case of where rownum = 1, the first row passes the test, is output and rownum goes
to 2. No other row ever satisfies the predicate and rownum stays at 2 for the rest of
the query.
in the case of where rownum = 2, the first row is rownum 1, it fails. The next row is
ALSO rownum = 1 and likewise fails. And so on. There can be NO row 2 if there is not a
row 1.
rownum的用法oracle
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