SELECT ename
, job
, CASE deptno
WHEN 10
THEN 'ACCOUNTS'
WHEN 20
THEN 'SALES'
ELSE 'UNKNOWN'
END AS department
FROM emp /* !!! */
WHERE department = 'SALES'
这个失败了:
ORA-00904: "%s: invalid identifier"
有没有办法在 Oracle 10.2 SQL 中克服这个限制?如何在 where 子句中使用“case 表达式列”?