无法引用新列？

Question

我无法为新创建的 'Role1' 列添加条件：

SELECT NVL(SUBSTR(ACCESS_PATH_INFO, 0, INSTR(ACCESS_PATH_INFO, '>')-1), ACCESS_PATH_INFO) AS Role1
from INCIDENTS
where Role1 = 'DB'

我需要创建此列以删除第一个“>”之后的所有数据：

DB1238 > DB102839 > DB10293892804
HJ3948203 > HJ10293 > HJ11

Role1
=====  
DB1238 
HJ3948203

尝试在查询中引用新列 'Role1' 时出现的错误是：

ORA-00904: "ROLE1": invalid identifier

我必须更改什么才能在 WHERE 子句中使用新列？

Answer 1

请尝试

SELECT * 
FROM (SELECT NVL(SUBSTR(ACCESS_PATH_INFO, 0, 
                        INSTR(ACCESS_PATH_INFO, '>') - 1
                       ), ACCESS_PATH_INFO
                ) AS Role1
      FROM INCIDENTS
     ) t1
WHERE t1.Role1 = 'DB'

无法引用新列？

Not able to reference new column?

sql

oracle

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