Question

我是sql的新手，我无法弄清楚如何使用带有pl / sql变量的别名的连接。这类似于我的匿名块看起来像

DECLARE
 l_count PLS_INTEGER;  
 l_name EmpTable.Name%Type;
BEGIN
   FOR l_row In (
     Select * 
      From User_Tab_Columns
     Where Table_Name = 'EmpTable')
   Loop
     l_name := l_row.Name;
     Select Count(A.l_name)
       INTO l_count
       FROM EmpTable A
      INNER JOIN CustTable B on A.id = B.emp_id;
     DBMS_OUTPUT ("The number of employees who are also customers are " || l_count);
   END LOOP;
END;

我收到错误＆＃39; l_name＆＃39;必须声明＆＃39;和＆＃34; A＆＃34;。＆＃34; l_name＆＃34;不合法的识别符。流程对我来说非常有意义。我应该知道一些细微差别吗？

Answer 1

l_name是一个变量，不是SQL表达式的一部分。我也更喜欢使用NUMBER和PLS_INTEGER。我想你会做这样的事情：

DECLARE
 l_count NUMBER;
BEGIN
   Select Count(A.Name)
     INTO l_count
     FROM EmpTable A
    INNER JOIN CustTable B on A.id = B.emp_id;
   DBMS_OUTPUT ("The number of employees who are also customers are " || l_count);
END;

如何在pl / sql中使用连接？

1 个答案: