在Oracle中，rtrim函數用于從字符串末尾刪除指定的字符
SELECT RTRIM(NVL(column_name, 'default_value'), 'trim_characters') FROM table_name;
SELECT RTRIM(CAST(column_name AS VARCHAR2(100)), 'trim_characters') FROM table_name;
SELECT RTRIM(SUBSTR(column_name, 1, 4000), 'trim_characters') FROM table_name;
SELECT CASE
WHEN column_name IS NULL THEN 'default_value'
WHEN LENGTH(column_name) > 4000 THEN SUBSTR(RTRIM(column_name, 'trim_characters'), 1, 4000)
ELSE RTRIM(column_name, 'trim_characters')
END AS trimmed_column
FROM table_name;
通過以上方法，可以有效地處理Oracle rtrim函數的異常情況。
