Sql 尝试获取用户名可以查看的文档数

因此，首先我需要创建一个UserPermissions表：

CREATE TABLE UserPermissions
(
Document varchar2(15),
UserName varchar(15)
);
INSERT INTO UserPermissions
Values('Policy', 'SYSTEM');
INSERT INTO UserPermissions
Values('Menu', 'JDOW');
INSERT INTO UserPermissions
Values('W2', 'USAM');
INSERT INTO UserPermissions
Values('Permissions', 'SYSTEM');
 INSERT INTO UserPermissions
Values('W2', ‘JDOW');
INSERT INTO UserPermissions
Values('Form 1040', 'USAM');
INSERT INTO UserPermissions
Values('Policy', 'JDOW');
INSERT INTO UserPermissions
Values('W2', 'SYSTEM');

然后，编写一个PL/SQL存储函数，将用户名作为输入，并返回用户有权查看的文档数。如果用户名不在表中，则过程应返回“未找到用户”。 到目前为止，这就是我所拥有的：

CREATE or REPLACE FUNCTION user_documents_func (UserName varchar2)
RETURN int AS
num_views INT;
BEGIN
SET num_views = (select count(*) from userpermissions);
IF num_views > 0 THEN
RETURN UserName || ' can view ' || num_views || ' document(s).';
ELSE 
Dbms_output.put_line('Username not found!');
END IF;
END;
/
SET SERVEROUTPUT ON;

SELECT语句缺少或选项无效时出错

我变了

SET num_views = (select count(*) from userpermissions);

致：

并以这种方式声明num_视图

CREATE or REPLACE FUNCTION user_documents_func (UserName varchar2, num_views int)

---

现在，我从关键字not found中得到错误，您需要首先声明变量，然后分配它

DECLARE @num_views int; // thought as sql-server

BEGIN
SELECT @num_views = count(*)  from userpermissions WHERE UserName LIKE input_var ;

IF @num_views > 0 THEN
RETURN UserName || ' can view ' || num_views || ' document(s).';
ELSE 
Dbms_output.put_line('Username not found!');
END IF;

---

返回用户名not found（未找到）和打印用户名之间存在差异。我已输入了declare（声明）和not getting（未获取）：在预期以下情况之一时遇到了符号declare（声明）：begin function pragma过程子类型current cursor delete exists Previous external language

DECLARE @num_views int; // thought as sql-server

BEGIN
SELECT @num_views = count(*)  from userpermissions WHERE UserName LIKE input_var ;

IF @num_views > 0 THEN
RETURN UserName || ' can view ' || num_views || ' document(s).';
ELSE 
Dbms_output.put_line('Username not found!');
END IF;