Question

我一直在研究将查询存储到变量中，但我遇到了麻烦。我一直收到错误

调用'||'
时参数的数目或类型错误

这就是我试过的

mydictionary = {'yummy tim tam':3, 'milk':2, 'chocolates':5, 'biscuit pudding':3, 'sugar':2}
recipes_book = "For today's lesson we will show you how to make biscuit pudding using yummy tim tam milk and rawsugar"
searcher = re.compile(r'{}'.format("|".join(mydictionary.keys())), flags=re.I | re.S)

for match in searcher.findall(recipes_book):
    print(match)

Answer 1

您可以通过名称来引用记录rec中的列：

DECLARE
  addresses VARCHAR(200);

  CURSOR allAddresses IS
    SELECT * 
    FROM ALL_ADDRESS;
BEGIN
  FOR rec IN allAddresses LOOP
    addresses := addresses || rec.house_number
                           || ' ' || rec.house_name
                           || ' ' || rec.address1
                           || ' ' || rec.address2;  
  END LOOP;
  DBMS_OUTPUT.PUT_LINE(addresses);
END;
/

Answer 2

您不能在表达式中直接使用CURSOR for loop迭代器。您只能将列名引用为rec.col1，rec.col2 ..等等

DECLARE
addresses VARCHAR(200);

 CURSOR allAddresses IS
      SELECT * 
      FROM ALL_ADDRESS;
BEGIN
 FOR rec IN allAddresses LOOP
      addresses := addresses || rec.<address_column>;  
 END LOOP;
 DBMS_OUTPUT.PUT_LINE(addresses);
END;

Answer 3

对于这种情况，你应该理解游标变量调用事物：

DECLARE
  addresses VARCHAR(200);

  CURSOR allAddresses IS
    SELECT * 
    FROM ALL_ADDRESS;
BEGIN
  FOR rec IN allAddresses LOOP
    addresses := addresses || rec.a;   -- A as attribute of your cursor
--- so your need to access your cursor attribute using loop name i.e rec
      END LOOP;
      DBMS_OUTPUT.PUT_LINE(addresses);
    END;
    /

每当您尝试访问光标记录时，都应该在属性之前调用cursor变量。希望它会帮助你..谢谢

Answer 4

试试这个 -

addresses := addresses || '' || rec;

在变量中存储查询

4 个答案: