Oracle 函数用法之decode
Oracle数据库: DECODE函数将该数值与一系列的序偶相比较,以决定最后的返回结果 。序偶序偶,就是成对出现;我们将这个函
Oracle数据库:
DECODE函数将该数值与一系列的序偶相比较,以决定最后的返回结果 。序偶序偶,就是成对出现;我们将这个函数与switch比较,我们发现他们基本相似,唯一不同的是switch将要比较的值放在case后面都加上了break中。
以下一个例子:(我直接从网上找的)
SELECT id,
DECODE(flag,’Y’,'Yes’,'N’,’No’,NULL,’None’,'Yes’)
FROM t_test;
当t_test的flag字段为Y时返回Yes,为N时返回No,为NULL时返回None,默认返回Yes。
看看我遇到的问题:
SELECT a.id,
a.user_name,
a.oper_time time2,
a.oper_type,
a.description,
a.oper_flag,
decode(a.oper_flag, '1', '成功', '失败') oper_flag,
a.ip,
b.true_name
FROM SEC_LOG_OPERATION a
left join sec_user b on a.user_name = b.user_name
where 1 = 1
order by oper_time desc
原来这红线部分是: decode(a.oper_flag, 1, '成功', '失败')
我在查询的时候会报错,,原因是oper_flag这个字段数据中有非数字类型,也就是这个字段不仅有1、0,还有“失败”,这样数据!=字符。所以我们把1当字符处理就可以了。

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