如何用空值替换空格并查询值不为空的地方？ （我在填表）

Question

我有两张桌子：

表1：

USER_NUM	FIRST_NAME	LAST_NAME
A123	Billy	Bob
A124	Billy	Joe
	Jane	Doe
	John	Doe

我正在尝试将USER_NAME 下的FIRST_NAME 和LAST_NAME 插入table2：

OWNER_ID	USER_NUM	USER_NAME
111	A123
112	A124

使用这个查询：

BEGIN
  FOR c1 IN (SELECT UPPER(t1.USER_NUM) number
                    ,t1.FIRST_NAME || ' ' || LAST_NAME user_name
               FROM table1 t1
              INNER JOIN table2 t2
                 ON number = t2.USER_NUM
              WHERE regexp_replace(number, '[[:space:]]+', NULL) IS NOT NULL
             )
  LOOP
    INSERT INTO table2 (USER_NAME) values (c1.user_name)
  END LOOP;
END;

问题是，如果我隔离我的选择语句，我仍然会得到 USER_NUM 的空白值，表格如下所示：

USER_NUM	USER_NAME
A123	Billy Bob
A124	Billy Joe
	Jane Doe
	John Doe

我收到一条错误消息，提示我无法在表中插入空值。

如何去除USER_NUM 中的这些空白值？

Answer 1

你想要update:

update table2 t2
    set user_name = (select t1.FIRST_NAME || ' ' || t1.LAST_NAME
                     from table1 t1
                     where t1.user_num = t2.user_num
                    )
    where exists (select 1
                  from table1 t1
                  where t1.user_num = t2.user_num
                 );