Question

我想从我定义的函数返回一个简单的varchar值：

CREATE FUNCTION getCustomerType (@orderNumber INT)
    RETURNS VARCHAR(30)
AS
Return 
    (
    select custtype from Customer c 
        join order o on o.customerid =  c.customerid
    where o.orderNumber = @orderNumber 
 )
GO

select getCustType(1063609)

应该返回订单＃1063609的客户类型但未通过

Answer 1

我会将函数的语法改为：

CREATE FUNCTION dbo.getCustomerType (@orderNumber INT)
    RETURNS VARCHAR(30)
AS
begin
  declare @custtype varchar(30)
  SET @custtype = (select custtype 
                      from dbo.Customer c 
                      join dbo.[order] o 
                        on o.customerid =  c.customerid
                      where o.orderNumber = @orderNumber)

  return @custtype
end

然后，当您使用架构（下面的dbo.）调用该函数时，您将使用：

select dbo.getCustomerType(10636909)

请参阅SQL Fiddle with Demo

该函数也可以写成（感谢@MartinSmith）：

CREATE FUNCTION getCustomerType (@orderNumber INT)
    RETURNS VARCHAR(30)
AS
begin
  return (select custtype 
                      from dbo.Customer c 
                      join dbo.[order] o 
                        on o.customerid =  c.customerid
                      where o.orderNumber = @orderNumber)
end

请参阅SQL Fiddle with Demo

从自定义T-SQL函数返回Varchar

1 个答案: