sql - 尝试在 SQL Plus 查询中小写列时出错

Question

好的，我正在使用 SQL Plus，我正在尝试查看表和我要以小写形式查看的列之一。这应该很容易，但由于某种原因它不起作用。我正在使用的代码是

SELECT CUSTOMER_NUM, CUSTOMER_ADD (LOWER)CUSTOMER_FIRST, (UPPER)CUSTOMER_LAST
FROM CUSTOMER;

我得到的错误是 ORA-00904: "CUSTOMER_LAST": invalid identifier

Answer 1

尝试lower(customer_first)并 upper(customer_last)

Answer 2

lower 和 upper 是函数调用，在 CUSTOMER_ADD 之后你也缺少昏迷。正确的sql应该是

SELECT CUSTOMER_NUM, CUSTOMER_ADD, LOWER(CUSTOMER_FIRST), UPPER(CUSTOMER_LAST) FROM CUSTOMER;