Question

跟随嵌套循环有什么问题，它会抛出以下错误：

ORA-00936：缺少表达

SET SERVEROUT ON;
SET FEED OFF;
DECLARE
schema_name varchar2(100);
table_name varchar2(100);

    BEGIN

        FOR outer_rec IN (select * from  scott.table_list) LOOP  

            FOR inner_rec IN (select a.* from all_tab_columns a where a.column_name =outer_rec.table_name(+) and a.owner='SCOTT' order by a.table_name) LOOP
            dbms_output.put_line (q'[||]' ||inner_rec.column_name || q'[||'|@@@@|']');
            END LOOP;

        END LOOP;

    END;
/

Answer 1

由于您使用两个单独的游标，因此无法将结果外部连接在一起。处理此问题的更好方法是使用单个游标执行您需要完成的操作，如：

BEGIN
  FOR aRow IN (select *
                 FROM scott.table_list t
                 LEFT OUTER JOIN all_tab_columns a
                   ON (a.owner = 'SCOTT' AND
                       a.table_name = t.table_name)
                 order by a.table_name)
  LOOP
    dbms_output.put_line (q'[||]' || aRow.column_name || q'[||'|@@@@|']');
  END LOOP;
END;

请注意，这也使用ANSI语法进行左外连接，这比旧的Oracle风格（（+））语法更受欢迎。

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Answer 2

我会这样写（也就是说，你的变量没有被使用）：

SET SERVEROUT ON;
SET FEED OFF;
DECLARE
  schema_name VARCHAR2(100);
  table_name  VARCHAR2(100);

  CURSOR c_get_tables IS
    SELECT * FROM scott.table_list;

  CURSOR c_get_all(c_name_in IN scott.table_name%TYPE) IS
    SELECT a.*
      FROM all_tab_columns a
     WHERE a.table_name = c_name_in(+)
       AND a.owner = 'SCOTT'
     ORDER BY a.table_name;

BEGIN

  FOR outer_rec IN c_get_tables
  LOOP

    FOR inner_rec IN c_get_all(outer_rec.table_name)
    LOOP
      dbms_output.put_line(q'[||]' || inner_rec.column_name ||
                           q'[||'|@@@@|']');
    END LOOP;

  END LOOP;

END;
/

Answer 3

试试这个

SET SERVEROUT ON;
SET FEED OFF;
DECLARE
schema_name varchar2(100);
table_name varchar2(100);

BEGIN

    FOR outer_rec IN (select * from  scott.table_list) LOOP  

        FOR inner_rec IN (select a.* from all_tab_columns a where a.table_name =outer_rec.table_name and a.owner='SCOTT' order by a.table_name) LOOP
        dbms_output.put_line (q'[||]' ||inner_rec.column_name || q'[||'|@@@@|']');
        END LOOP;

    END LOOP;

END;

/

PL / SQL嵌套循环错误

3 个答案: