如何在Oracle SQL的SELECT语句中实现自定义列的除法运算？

错误原因 #

你当前SQL里的'Num1' / 'Num2'是问题核心：单引号包裹的是字符串字面量，不是你定义的列别名。Oracle会尝试把字符串'Num1'转换成数字进行除法运算，这显然会失败，所以抛出ORA-01722错误。

修正后的SQL写法 #

因为Num1和Num2是你硬编码的固定数值，最简单的写法就是直接用数值计算：

SELECT 
    REQUESTID AS "Request ID",
    10 AS "Num1",
    5 AS "Num2",
    10 / 5 AS "N1_DividedBy_N2_Result"
FROM 
    RM.CUSTINCDT;

如果后续需要让Num1和Num2是动态列（比如从表中取值），可以用子查询/CTE先定义这两个列，再引用：

WITH cte AS (
    SELECT 
        REQUESTID AS "Request ID",
        10 AS "Num1",
        5 AS "Num2"
    FROM RM.CUSTINCDT
)
SELECT 
    "Request ID",
    "Num1",
    "Num2",
    "Num1" / "Num2" AS "N1_DividedBy_N2_Result"
FROM cte;

执行结果 #

修正后执行就能得到你期望的结果：

内容的提问来源于stack exchange，提问作者Student_OKIE