oracle取一条记录中多个列的最大值和最小值

1.使用oracle内置的greatest()和least()函数，具体示例如下：

select 5 as col1,6 as col2,9 as col3,1 as col4 from dual;

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col1 | col2 |col3 |col4

5       6      9      1

select greatest(5,6,9,1) as maxcol, least(5,6,9,1) as mincol from dual;

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maxcol |  mincol

9            1